Method and apparatus for power control for wireless transmissions on multiple component carriers associated with multiple timing advances

ABSTRACT

A method and apparatus for power control for wireless transmissions on multiple component carriers associated with multiple timing advances are disclosed. A wireless transmit/receive unit (WTRU) may perform power scaling or other adjustments on physical channels in each subframe to be transmitted on component carriers that belong to different timing advance groups (TAGs) if a sum of the transmit powers of the channels would or is to exceed a configured maximum output power for that subframe where each TAG may be associated with a separate timing advance value for uplink transmissions. The WTRU may adjust the transmit power of at least one physical channel if a sum of transmit powers in an overlapping portion of subframes of a less advanced TAG and a more advanced TAG would or is to exceed a configured maximum WTRU output power during the overlap.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Nos.61/555,853 filed Nov. 4, 2011, 61/591,050 filed Jan. 26, 2012,61/612,096 filed Mar. 16, 2012, 61/644,726 filed May 9, 2012, 61/677,750filed Jul. 31, 2012, and 61/705,436 filed Sep. 25, 2012, the contents ofwhich are hereby incorporated by reference herein.

BACKGROUND

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so on. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include code division-multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, Third Generation PartnershipProject (3GPP) Long Term Evolution (LTE) systems, and orthogonalfrequency division multiple access (OFDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is LTE. LTE is a set of enhancements to theUniversal Mobile Telecommunications System (UMTS) mobile standardpromulgated by 3GPP. It is designed to better support mobile broadbandInternet access by improving spectral efficiency, lowering costs,improving services, making use of new spectrum, and better integratingwith other open standards using OFDMA on the downlink (DL), singlecarrier frequency division multiple access (SC-FDMA) on the uplink (UL),and multiple-input multiple-output (MIMO) antenna technology.

Uplink transmitter power control in a mobile communication systembalances the need for sufficient energy transmitted per bit to achieve adesired quality-of-service (e.g., data rate and error rate), against theneed to minimize interference to other users of the system and tomaximize the battery life of the mobile terminal. To accomplish thisgoal, uplink power control has to adapt to the characteristics of theradio propagation channel, including path loss, shadowing, fast fadingand interference from other users in the same cell and adjacent cells.

SUMMARY

A method and apparatus for power control for wireless transmissions onmultiple component carriers associated with multiple timing advances aredisclosed. A wireless transmit/receive unit (WTRU) may perform powerscaling or other adjustments on physical channels in each subframe to betransmitted on component carriers that belong to different timingadvance groups (TAGs) if a sum of the transmit powers of the channelswould or is to exceed a configured maximum output power for thatsubframe where each TAG may be associated with a separate timing advancevalue for uplink transmissions. The WTRU may adjust the transmit powerof at least one physical channel if a sum of transmit powers in anoverlapping portion of subframes of a less advanced TAG and a moreadvanced TAG would or is to exceed a configured maximum WTRU outputpower during the overlap.

The WTRU may drop a sounding reference signal (SRS) on a condition thatanother physical channel is scheduled to be transmitted in anoverlapping symbol on any component carrier. The WTRU may send a powerheadroom report to a network including a configured maximum WTRU outputpower for a present subframe on a condition that the configured maximumWTRU output power does not equal a configured maximum WTRU output powerfor any serving cell or a sum of configured maximum WTRU output powersfor serving cells.

The WTRU may transmit a physical random access channel (PRACH) at aconstant power level determined for a first subframe of the PRACH. Aguard symbol may be included in a component carrier to avoid overlappingchannels.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A;

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A;

FIG. 2 shows an example subframe which is a cell-specific SRS subframein one component carrier (CC) but not another;

FIG. 3 shows an example of multiple timing advance groups (TAGs) with adifferent timing advance (TA) applied to each TAG;

FIGS. 4A and 4B show examples of cross-subframe conflicts between SRSand other channel transmissions;

FIGS. 5A-5C show examples of transmissions of SRS and other channels incase of less than one symbol TA difference between CCs;

FIGS. 6A-6C show examples of SRS and other channel transmissions in caseof TA difference of more than one symbol;

FIG. 7 shows an example of cross-subframe conflicts for the case of SRSbeing at the front of a subframe;

FIG. 8 shows an example of SRS included in the middle of subframe;

FIG. 9 shows an example of the use of measurements to determine a TAdifference between two cells;

FIG. 10 shows an example of potential interference between the pastsubframe to the present subframe;

FIG. 11 shows an example of overlap of a physical random access channel(PRACH) in the past subframe into the present subframe;

FIG. 12 shows an example of a guard symbol included in the presentsubframe in a more advanced CC;

FIGS. 13 and 14 show examples of transient periods without SRS and withSRS, respectively;

FIGS. 15 and 16 show examples of expanded transient periods for non-SRSand SRS transmissions, respectively;

FIG. 17 shows an example in which per-symbol scaling is applied to thesymbols in the overlap;

FIG. 18A shows an example in which transmit powers in the overlap arerescaled after the power is determined for the two adjacent subframes;

FIG. 18B shows an example in which the transmit powers in the overlapare scaled separately from the transmit powers in the non-overlappingregions;

FIG. 19 shows an example overlap region based on uplink (UL) timing; and

FIG. 20 shows an example overlap region including the transient regions.

DETAILED DESCRIPTION

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the networks 112. By way of example, the base stations 114 a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a HomeNode B, a Home eNode B, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it will be appreciated that the basestations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it will be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It will be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 106 and/or the removable memory 132.The non-removable memory 106 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 104 and the core network 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 106.

The RAN 104 may include eNode-Bs 140 a, 140 b, 140 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 140 a, 140 b, 140c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 140 a, 140 b, 140 c may implement MIMO technology. Thus,the eNode-B 140 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 140 a, 140 b, 140 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1C, theeNode-Bs 140 a, 140 b, 140 c may communicate with one another over an X2interface.

The core network 106 shown in FIG. 1C may include a mobility managementgateway (MME) 142, a serving gateway 144, and a packet data network(PDN) gateway 146. While each of the foregoing elements are depicted aspart of the core network 106, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 142 may be connected to each of the eNode-Bs 142 a, 142 b, 142 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 142 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 142 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may be connected to each of the eNode Bs 140 a,140 b, 140 c in the RAN 104 via the S1 interface. The serving gateway144 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 144 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 144 may also be connected to the PDN gateway 146,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 106 may facilitate communications with other networks.For example, the core network 106 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 106 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 106 and the PSTN 108. In addition, the corenetwork 106 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

In 3GPP LTE, for example according to LTE Release 8 (R8), a WTRU maytransmit on one carrier to one cell which may be referred to as itsserving cell. A WTRU supporting carrier aggregation, for exampleaccording to LTE Release 10 (R10), may transmit on multiple carrierssimultaneously and may have multiple serving cells.

In some embodiments, a cell includes a combination of downlink and/oruplink resources. Each of the downlink and uplink resource sets may beassociated to a carrier frequency, which may be the center frequency ofthe cell, and a bandwidth.

A WTRU supporting carrier aggregation, for example according to LTE R10,may be configured with one or more serving cells (or component carriers(CCs)) and for each CC the WTRU may be configured for UL communication.It is contemplated that the CC and the serving cell may be usedinterchangeably and still be consistent with the embodiments containedherein.

A WTRU supporting carrier aggregation may communicate with one primarycell (PCell) and one or more secondary cells (SCell). The terms cell andserving cell may be used interchangeably.

In the LTE, a WTRU UL transmission on a CC in any given subframe maycontain at least one of a physical random access channel (PRACH), aphysical uplink shared channel (PUSCH), or a physical uplink controlchannel (PUCCH). UL transmissions may be managed by subframe. Forexample, the transmission of a PUSCH and/or a PUCCH, each at sometransmit power, in any given subframe may be managed separately fromPUSCH and/or PUCCH transmissions in any other subframe. On a CC, PUSCHand PUCCH transmissions may use some set of subcarriers, for example asindicated by their respective grant or other configuration orallocation, and, with the possible exception of certain symbols, forexample symbols in which the WTRU may transmit demodulation referencesignals (DMRS) or symbols which may be used or reserved for a soundingreference signal (SRS), may use all of the symbols in the subframe. Forexample, for the normal cyclic prefix (CP) case, a PUSCH may betransmitted in 12 of the 14 symbols of the subframe, with DMRS insymbols 3 and 10, and a PUCCH may be transmitted in 8 of the 14 symbols,with DMRS in symbols 2-4 and 9-11.

In certain subframes, a WTRU may transmit an SRS. A WTRU may transmit anSRS periodically based on a schedule and transmission parameters whichmay be provided to the WTRU by the evolved NodeB (eNB), for example viaone or more of broadcast signaling and radio resource control (RRC)dedicated signaling. Cell-specific SRS configuration may define thesubframes in which the SRS is permitted to be transmitted by WTRUs for agiven cell. WTRU-specific SRS configuration may define the subframes andthe transmission parameters which may be used by a specific WTRU. In itsWTRU-specific subframes, a WTRU may transmit an SRS in the last symbolacross the entire frequency band of interest with a single SRStransmission, or across part of the band with hopping in the frequencydomain in such a way that a sequence of SRS transmissions may jointlycover the frequency band of interest. A particular WTRU may transmit anSRS in WTRU-specific subframes which are a subset of the cell-specificSRS subframes. A WTRU may also transmit an SRS on demand in response toan aperiodic SRS request from the network which may be included in adownlink control information (DCI) format which may also provide an ULgrant. Separate WTRU-specific SRS configurations may be provided to theWTRU for periodic and aperiodic SRS transmissions.

Certain rules may apply in cell-specific SRS subframes. In cell-specificSRS subframes of a particular CC in which a PUSCH is also scheduled fortransmission by a certain WTRU on that CC, the certain WTRU may shortenthe PUSCH transmission (e.g., the certain WTRU may not map a PUSCH to ortransmit a PUSCH in the last symbol of the subframe) if the PUSCHtransmission partly or fully overlaps with the cell-specific SRSbandwidth. If there is no overlap, the certain WTRU may not shorten thePUSCH transmission. In either case, the certain WTRU may transmit thePUSCH in the subframe, and if this is a WTRU-specific SRS subframe forthe certain WTRU, the certain WTRU may also transmit an SRS in thesubframe where the PUSCH and the SRS may be transmitted in theirrespective symbols in the subframe.

In cell-specific SRS subframes of a particular CC in which a certainPUCCH format, for example PUCCH format 1, 1a, 1b, or 3, is alsoscheduled for transmission by a certain WTRU on that CC and a parameter,for example ackNackSRS-SimultaneousTransmission, is a certain value suchas TRUE for at least the certain WTRU, the certain WTRU may use ashortened PUCCH format which does not use the last symbol of thesubframe (e.g., the certain WTRU may not map a PUCCH to or transmitPUCCH in the last symbol of the subframe). The certain WTRU may transmita PUCCH in the subframe, and if this is a WTRU-specific SRS subframe forthe certain WTRU, the certain WTRU may also transmit an SRS in thesubframe where the PUCCH and the SRS may be transmitted in theirrespective symbols in the subframe. If another PUCCH format is scheduledfor transmission or the parameter, e.g.,ackNackSRS-SimultaneousTransmission, is a certain other value such asFALSE for at least the certain WTRU, the certain WTRU may transmit aPUCCH using the regular (e.g., non-shortened) format and may drop (e.g.,may not transmit) the SRS.

A WTRU may synchronize its reception and transmission timing to thereceived frame timing of a reference cell. With carrier aggregation(CA), the reference cell may be a primary cell (PCell) or a secondarycell (SCell). The timing of received frame boundaries may vary over timedue to WTRU motion and/or other factors, (e.g., oscillator drift), and aWTRU may autonomously adjust its timing accordingly. In addition, theWTRU may apply a timing advance (TA) to the transmitted signals, (e.g.,the WTRU may start transmission of a given UL subframe some amount oftime, (e.g., the applied TA), before the start of the corresponding DLsubframe. The eNB may provide TA commands to each WTRU which maycommunicate with it in the UL or which may be under its control, and theeNB may provide such commands with the intent that UL transmissions fromthe WTRUs in any given subframe intended for a certain cell arrive atthe certain cell at nominally the same time. The WTRU may alsoautonomously adjust its uplink timing according to the received downlinkframe of the reference cell, and that timing may change.

The term “timing advance group” (TAG) includes, without loss ofgenerality, a group of one or more serving cells, which may beconfigured by higher layer signaling such as RRC signaling, for which aWTRU may for each cell in the group apply the same TA value or offset,for example, using a downlink timing reference for each cell whichreference may or may not be the same for all cells of a group.Application of TA may be limited to cells with configured uplink. TheTAG may be limited to cells with configured uplink. The primary TAG(pTAG) may be the TAG that contains the PCell. The pTAG may or may notcontain SCells. A secondary TAG (sTAG) may be a TAG that does notcontain the PCell. An sTAG may contain SCells only and may contain atleast one cell with configured uplink.

A WTRU configured for CA may transmit on more than one serving cell inthe same subframe. The terms “serving cell” and “CC” may be usedinterchangeably. In certain cases, such as intra-band CA (e.g., theaggregated CCs are in the same band), the WTRU may use the same DLtiming reference and the same timing advance for the aggregated CCs andas a result, the WTRU may transmit subframes in the aggregated CCs timealigned (e.g., exactly or almost exactly time aligned) with each other.

TA and ΔTA may be replaced by UL timing and UL timing difference,respectively in any of the embodiments disclosed hereafter. The terms“subframe” and “transmission time interval” (TTI) may be usedinterchangeably. Subframes i and i+1 may represent consecutive subframeswhich may overlap in time and N and N+1 may be used instead of i andi+1. The terms “power backoff” and “power reduction” may be usedinterchangeably. Italicized and non-italicized notations may be usedinterchangeably.

For each subframe in which a WTRU may transmit, the WTRU may set thetransmit power of the physical channels to be transmitted. The WTRU maydetermine a PUSCH, a PUCCH, and/or an SRS transmit power in accordancewith at least one of the following:

$\begin{matrix}{{{{P_{{PUSCH},c}(i)} = {\min \begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{{10\; {\log_{10}( {M_{{PUSCH},c}(i)} )}} + {{P_{{O\_ PUSCH},c}(j)} \cdot}} \\{{PL}_{c} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}};}\mspace{20mu} {{or},}} & {{Equation}\mspace{14mu} (1)} \\{{{P_{{PUSCH},c}(i)} = {\min \begin{Bmatrix}{{10\; {\log_{10}( {{{\hat{P}}_{{CMAX},c}(i)} - {{\hat{P}}_{PUCCH}(i)}} )}},} \\\begin{matrix}{{10\; {\log_{10}( {M_{{PUSCH},c}(i)} )}} + {P_{{O\_ PUSCH},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}};} & {{Equation}\mspace{14mu} (2)} \\{{{P_{{PUCCH},c}(i)} = {\min \begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0{\_ PUCCH}} + {PL}_{c} + {h( {n_{CQI},{n_{{HARQ},}n_{SR}}} )} +} \\{{\Delta_{F\_ PUCCH}(F)} + {\Delta_{T \times D}( F^{\prime} )} + {g(i)}}\end{matrix}\end{Bmatrix}}};} & {{Equation}\mspace{14mu} (3)} \\{{P_{{SRS},c}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},{{P_{{SRS\_ OFFSET},c}(m)} + {10\; {\log_{10}( M_{{SRS},c} )}} +}} \\{{P_{{O\_ PUSCH},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + {f_{c}(i)}}\end{Bmatrix}.}}} & {{Equation}\mspace{14mu} (4)}\end{matrix}$

P_(PUSCH,c)(i) and P_(SRS,c)(i) may be the power of a PUSCH and an SRS,respectively, for CC c in subframe i, P_(PUCCH)(i) may be the power of aPUCCH in subframe i, and P_(CMAX,c)(i) may be the configured maximumoutput power for CC c in subframe i and each of these values may be indBm. {circumflex over (P)}_(PUCCH)(i) may be the linear value ofP_(PUCCH)(i) {circumflex over (P)}_(PUSCH,c)(i) may be the linear valueof P_(PUSCH,c)(i), and {circumflex over (P)}_(CMAX,c)(i) may be thelinear value of P_(CMAX,c)(i). The WTRU may set P_(CMAX,c)(i) withinallowed limits.

M_(PUSCH,c)(i) may be the bandwidth of the PUSCH resource assignment andmay be expressed in number of resource blocks valid for subframe i andserving cell c.

P_(O) _(—) _(PUSCH,c)(j) may be a parameter composed of the sum of acomponent P_(O) _(—) _(NOMINAL) _(—) _(PUSCH,c)(i) which may be providedby higher layers for j=0 and 1 and a component P_(O) _(—) _(UE) _(—)_(PUSCH,c)(j) which may be provided by higher layers for j=0 and 1 forserving cell c. For PUSCH (re)transmissions corresponding to asemi-persistent grant j may be 0, for PUSCH (re)transmissionscorresponding to a dynamic scheduled grant j may be 1 and for PUSCH(re)transmissions corresponding to the random access response grant jmay be 2. For j=2, the value of P_(O) _(—) _(NOMINAL) _(—) _(PUSCH,c)(j)may be set based on a random access procedure results and P_(O) _(—)_(UE) _(—) _(PUSCH,c)(j) may be 0. α_(c)(j) may be a parameter providedby higher layers or may be a fixed value. PL_(c) may be a downlinkpathloss estimate calculated in the WTRU for serving cell c. Δ_(TF,c)(i)may be a parameter computed by the WTRU based on parameters provided byhigher layers and/or one or more of the number of code blocks, size ifeach code block, the number of channel quality indicator (CQI)/precodingmatrix indicator (PMI) bits to be transmitted, and the number ofresource elements. ƒ_(c)(i) may be a power control accumulation termwhich may be an accumulation of transmit power control (TPC) commands,for example for PUSCH on CC c.

P_(O) _(—) _(PUCCH) may be a parameter composed of the sum of aparameter P_(O) _(—) _(NOMINAL) _(—) _(PUCCH) which may be provided byhigher layers and a parameter P_(O) _(—) _(UE) _(—) _(PUCCH) which maybe provided by higher layers. h(n_(CQI), n_(HARQ), n_(SR)) may be aPUCCH format dependent value which may be a function of the number ofCQI, hybrid automatic repeat request (HARQ), and Scheduling Request bitsto be transmitted. The parameter Δ_(F) _(—) _(PUCCH)(F) may be a PUCCHformat dependent parameter which may be provided by higher layers.Δ_(T×D)(F′) may be a PUCCH format dependent parameter which may beprovided by higher layers if the WTRU is configured by higher layers totransmit PUCCH on two antenna ports and may be 0 otherwise. g(i) may bea power control accumulation term which may be an accumulation of TPCcommands, for example for PUCCH.

P_(SRS) _(—) _(OFFSET,c)(m) may be a parameter provided by higher layersand m may have a value which represents the SRS mode which may beperiodic or aperiodic. M_(SRS,c) may be the bandwidth of the SRStransmission in subframe i for serving cell c and may be expressed innumber of resource blocks. The parameters in the SRS equation which havethe same notation as in the PUSCH equations may use the same values asthose used for the PUSCH power for the same CC c.

The WTRU may determine, (e.g., first determine), the power of eachchannel to be transmitted. If the sum of the channel transmit powers,(e.g., the determined channel transmit powers), would or is to exceedthe configured maximum output power, (e.g., the total configured maximumoutput power), of the WTRU, the WTRU may scale the transmit power of thechannels, such as per a set of rules, such that after the scaling, thesum of the transmit powers would not or does not exceed the configuredmaximum output power, (e.g., the total configured maximum output power),of the WTRU, P_(CMAX).

For example, the WTRU may scale {circumflex over (P)}_(PUSCH,c)(i) forserving cell c in subframe i such that the following condition is met:

$\begin{matrix}{{\sum\limits_{c}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq {( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)}} ).}} & {{Equation}\mspace{14mu} (5)}\end{matrix}$

{circumflex over (P)}_(PUCCH)(i) may be the linear value ofP_(PUCCH)(i), {circumflex over (P)}_(PUSCH,c)(i) may be the linear valueof P_(PUSCH,c)(i), {circumflex over (P)}_(CMAX)(i) may be the linearvalue of the WTRU total configured maximum output power P_(CMAX) insubframe i, and w(i) may be a scaling factor of {circumflex over(P)}_(PUSCH,c)(i) for serving cell c where 0≦w(i)≦1.

Scaling, or otherwise adjusting, transmit power may follow a set ofrules which may be based on channel priority. For example, thepriorities may be, from the highest to the lowest: a PUCCH, a PUSCH withuplink control information (UCI), and a PUSCH without UCI and a higherpriority channel may use all of the available transmit power, and thenext lower priority channel may use any remaining available transmitpower. When there are multiple channels of the same priority, if thereis not enough power for all of them, power may be shared equally amongstthem such that the same relative power reduction is applied to eachchannel. Once a power reduction is applied to a channel or group ofchannels, if no power is available to the next lower priority channel,those lower priority channels may not be transmitted.

A WTRU may scale an SRS transmit power if the sum of SRS transmit powersin more than one CC would or is to exceed the total configured maximumoutput power of the WTRU, for example:

$\begin{matrix}{{\sum\limits_{c}{{w(i)} \cdot {{\hat{P}}_{{SRS},c}(i)}}} \leq {{{\hat{P}}_{CMAX}(i)}.}} & {{Equation}\mspace{14mu} (6)}\end{matrix}$

{circumflex over (P)}_(SRS,c)(i) may be the linear value ofP_(SRS,c)(i).

The WTRU may determine (or set) the configured maximum WTRU output powerfor serving cell c, P_(CMAX,c), within a lower and upper bound asfollows:

P _(CMAX) _(—) _(L,c) ≦P _(CMAX,c) ≦P _(CMAX) _(—) _(H,c);  Equation (7)

The lower and upper bound may, for example be defined as:

P _(CMAX) _(—) _(L,c)=MIN{P _(EMAX,c) −ΔT _(C,c) ,P_(PowerClass)−MAX(MPR _(c) +A-MPR _(c) +ΔT _(IB,c) ,P-MPR _(c))−ΔT_(C,c)};and  Equation (8)

P _(CMAX) _(—) _(H,c)=MIN{P _(EMAX,c) ,P _(PowerClass)}.  Equation (9)

P_(EMAX,c) may be the maximum allowed WTRU output power which may besignaled by higher layers for the serving cell c, P_(PowerClass) may bethe maximum WTRU power, for example according to its power class, andmay not take tolerance into account, maximum power reduction (MPRs),additional maximum power reduction (A-MPR_(c)), power management powerreduction (P-MPRs), ΔT_(C,c), and ΔT_(IB,c) may be terms for the servingcell c that allow the WTRU to reduce its maximum output power forcertain permitted reasons such as to meet emissions requirements andspecific absorption requirements (SAR), among others. These values maybe in dB.

For carrier aggregation with UL serving cells, the WTRU may determine(or set) the total configured maximum WTRU output power P_(CMAX) withina lower and upper bound as follows:

P _(CMAX) _(—) _(L) _(—) _(CA) ≦P _(CMAX) ≦P _(CMAX) _(—) _(H) _(—)_(CA);  Equation (10)

The lower and upper bound may, for example, be defined for inter-bandcarrier aggregation as follows:

P _(CMAX) _(—) _(L) _(—) _(CA)=MIN{10 log₁₀ ΣMIN[p _(EMAX,c)/(Δt_(C,c)),p _(PowerClass)/(mpr _(c) ·a-mpr _(c) ·Δt _(C,c) ·Δt _(IB,c)),p_(PowerClass)/(pmpr _(c) ·Δt _(C,c))],P _(PowerClass)}; and  Equation(11)

P _(CMAX) _(—) _(H) _(—) _(CA)=MIN{10 log₁₀ Σp _(EMAX,c) ,P_(PowerClass)}.  Equation (12)

p_(EMAX,c) may be the linear value of P_(EMAX,c), Δt_(C,c) may be thelinear value of ΔT_(C,c), p_(PowerClass) may be the linear value ofP_(PowerClass), and mprc, a-mprc and pmprc may be the linear values ofMPRc, A-MPRc and P-MPRc, respectively.

In some embodiments P_(CMAX) may be equivalent to P_(CMAX)(i) and theterms may be used interchangeably.

The measured maximum output power P_(UMAX) over serving cells may bedefined or required to be within the following range:

P _(CMAX) _(—) _(L) _(—) _(CA) −T(P _(CMAX) _(—) _(L) _(—) _(CA))≦P_(UMAX) ≦P _(CMAX) _(—) _(H) _(—) _(CA) +T(P _(CMAX) _(—) _(H) _(—)_(CA));  Equation (13)

P _(UMAX)=10 log₁₀ Σp _(UMAX,c).  Equation (14)

T(P) may be an allowed tolerance that is a function of the value of Pand p_(UMAX,c) may denote the measured maximum output power for servingcell c expressed in linear scale.

When a WTRU is transmitting on multiple CCs, certain rules may applygoverning the transmission of SRS in one CC based on what may betransmitted in another CC. For example, a subframe may be acell-specific SRS subframe in one CC but not another. FIG. 2 shows anexample in which a subframe is a cell-specific SRS subframe of one CC,CC1, but not another, CC2.

According to an example set of rules, such as those defined for LTE R10,if the WTRU is scheduled to transmit an SRS in one CC, (e.g., CC1), andthe WTRU is also scheduled to transmit a PUSCH or a PUCCH (with possibleexceptions which may be format dependent) where such transmissionincludes transmission in the last symbol 204 in another CC, (e.g., CC2),the WTRU may drop (e.g., may not transmit) the scheduled SRS in CC1. Ifthe WTRU is not scheduled to transmit a PUSCH or a PUCCH in CC2 or theWTRU is scheduled to transmit a PUSCH or a PUCCH in CC2 but suchtransmission does not include transmission in the last symbol 204 of CC2(e.g., because this is a cell-specific SRS subframe for CC2), the WTRUmay transmit a scheduled SRS 202 in CC1. The rules regarding PUCCH maybe dependent on the PUCCH format to be transmitted, for example, SRStransmission may have priority over PUCCH transmission for certain PUCCHformats such as PUCCH format 2 without HARQ-ACK.

A WTRU transmitting on multiple CCs may have a different DL timingreference and/or a different TA for one or more of those CCs. A timingadvance group (TAG) may be a set of CCs for which the WTRU has a commonDL timing reference and/or a common TA.

Given CCs using a different DL timing reference and/or a different TA,if the WTRU transmits on two or more such CCs nominally at the sametime, (i.e., nominally in the same subframe), the subframe and internalsymbol boundaries may not be time-aligned with each other, resulting insubframes and their internal symbols in one CC overlapping with those inone or more other CCs. FIG. 3 shows an example of multiple TAGs with adifferent TA applied to each TAG. TAG1 is more advanced than TAG2 inFIG. 3. It should be noted that the example in FIG. 3 shows two CCs ineach of two TAGs, but there may be any number of TAGs with any number ofCCs in each TAG. It should also be noted that the example in FIG. 3shows a time difference that may result in overlap of up to 2 symbols,but this is for example purposes and the time difference and overlap maybe any value.

Conventionally, transmit powers of UL channels, (e.g., P_(PUSCH,c)(i),P_(PUCCH)(i), P_(SRS,c)(i), and P_(PRACH)(i) or P_(PRACH,c)(i)), aredetermined with no consideration to an UL timing difference between CCs.However, when there is an UL timing difference between CCs, suchtransmit powers may need to be determined differently, for example toprevent the WTRU from exceeding maximum transmit power and/or causingexcessive interference at maximum transmit power when subframes of oneCC may overlap adjacent subframes of another CC.

A WTRU may receive uplink scheduling grants in the DL that direct theWTRU's UL transmissions. Uplink scheduling grants received in onesubframe, (e.g., subframe n), may yield UL transmissions in a latersubframe, (e.g., subframe n+4, for example for LTE FDD). A WTRU mayprocess a grant for one UL subframe at a time. In this example, for anygiven subframe n+4 for which an UL scheduling grant has been received insubframe n, at some point in time during the interval [n,n+4], the WTRUmay demodulate and decode the grant and perform the power processing forsubframe n+4. The power processing may include one or more of:determination of the various channels' transmit powers for subframe n+4,determination of scaling to not exceed WTRU total configured maximumoutput power, deciding to transmit or not transmit a scheduled SRS,puncturing a PUSCH and/or shortening a PUCCH to accommodate an SRS, andthe like.

Hereafter, one subframe, such as subframe n+4, is referred to as a“present” subframe, the previous subframe is referred to as a “past”subframe” and the next subframe is referred to as a “future” subframe.Decisions about a subframe such as a present subframe may be made, andin a practical WTRU implementation may typically be made, during somesubframe prior to the present subframe. Determination of power for apresent subframe may be impacted by transmissions in a past or futuresubframe. In an example WTRU implementation, transmissions (e.g., powerfor transmissions) in a past subframe may not be changed to accommodatetransmissions in a later (present) subframe, for example because thepast has already occurred and may not be able to be changed. In anotherexample, transmissions (e.g., power for transmissions) in a presentsubframe may not be changed to accommodate transmissions in a futuresubframe, for example because when the WTRU is making decisions aboutthe present subframe, it may not yet have full knowledge oftransmissions for the future subframe.

It should be noted that the above timing relationship of UL assignmentin subframe n and UL transmission in subframe n+4 is provided as anexample and the embodiments disclosed herein are applicable to anytiming relationship such as one which may correspond to any standard(e.g., LTE FDD or LTE TDD). In addition, use of subframe n+4 as apresent subframe is for example purposes and any subframe may beconsidered a present subframe with a subframe preceding it being a pastsubframe and a subframe after it being a future subframe and still beconsistent with the embodiments disclosed herein. In some embodiments ior N may be used to represent the present subframe with i−1 or N−1representing the past subframe and/or i+1 or N+1 representing the futuresubframe. Other notation may be used and still be consistent with theembodiments disclosed herein.

Conventionally, the rules for simultaneous transmission of an SRS andother channels by a given WTRU on different CCs are typically predicatedon the UL subframe boundaries of the CCs coinciding (e.g., exactly ornearly exactly coinciding), for example, assuming that there is nooverlap (e.g., adjacent subframe overlap) due to TA difference or no TAdifference among CCs. When there is a TA difference, the conventionalrules may not properly handle simultaneous SRS and other ULtransmissions. For example, in case of no TA difference, a WTRU may beallowed to transmit an SRS in one CC simultaneously with a shortenedPUSCH in another CC. However, when there is a TA difference, applyingthat rule may result in transmission of a PUSCH in one CC and an SRS inanother CC occurring within the same symbol period. This is referred toas cross-subframe conflicts (between past, present, and futuresubframes) between an SRS and other channels.

FIGS. 4A and 4B show examples of cross-subframe conflicts between an SRSand other channel transmissions. In case where an SRS is transmitted ina less advanced TAG as shown in FIG. 4A, an SRS 402 in the past subframemay conflict with a PUSCH and/or PUCCH 406 in the present subframe, anda PUSCH and/or PUCCH 408 in the future subframe may conflict with an SRS404 in the present subframe. In case where an SRS is transmitted in amore advanced TAG as shown in FIG. 4B, an SRS 412 in the past subframemay conflict with a PUSCH and/or PUCCH 416 in the past subframe, and aPUSCH and/or PUCCH 418 in the present subframe may conflict with an SRS414 in the present subframe.

Embodiments for handling an SRS and other UL channels that are scheduledfor simultaneous transmission in case of UL timing difference aredisclosed hereafter.

In one embodiment, a WTRU may not transmit an SRS simultaneously with aPUSCH and/or a PUCCH in the same symbol, and this may extend to adjacentsymbols or adjacent subframes. FIGS. 5A-5C show examples oftransmissions of an SRS and other channels in case of less than onesymbol TA difference between CCs. In these examples, the SRS istransmitted at the end of a subframe. In FIGS. 5A-5C, the horizontallycrosshatched symbol is an additional symbol (either in the current ornext subframe) that may be affected by the rules for simultaneous SRSand other UL channel transmissions in case of UL timing differencebetween CCs.

In FIG. 5A, an SRS 502 is scheduled in a more advanced CC. The WTRU maytransmit the scheduled SRS 502 for a given CC in subframe i if a PUSCHor a PUCCH is not mapped to both the last symbol 504 and the next tolast symbol 506 of another CC (less advanced CC) in subframe i. The WTRUmay drop the scheduled SRS 502 for a given CC in subframe i if a PUSCHor a PUCCH is mapped to the last symbol 504 or the next to last symbol506 of another CC (less advanced CC) in subframe i. For example, theWTRU may drop the scheduled SRS 502 if the WTRU uses a shortened PUCCHformat or a shortened PUSCH on another CC (less advanced CC) that doesnot use the last symbol 504 of subframe i but uses the next to lastsymbol 506 on that CC.

In FIG. 5B, an SRS is scheduled in a less advanced CC. In this case, across-subframe interference may occur between an SRS in a presentsubframe and other channels in a future subframe, or between an SRS in apast subframe and other channels in a present subframe. The WTRU maytransmit the scheduled SRS 512 for a given CC in subframe i if a PUSCHor a PUCCH is not mapped to both the last symbol 514 in subframe i andthe first symbol 516 in subframe i+1 of another CC (more advanced CC).The WTRU may drop a scheduled SRS 512 for a given CC in subframe i if aPUSCH or a PUCCH is mapped to the last symbol 514 in subframe i or thefirst symbol 516 in subframe i+1 of another CC (more advanced CC). Thismay be practical implementation, because the SRS is at the end of itssubframe and the WTRU may later (up until the point in time of actualSRS transmission) decide to not transmit SRS in the present subframe asit originally had determined to do so as part of the processing for thepresent subframe. In case the WTRU decides not to transmit the SRS, theWTRU may undo any PUSCH puncturing or PUCCH shortening as the WTRUoriginally determined to do so as part of the processing for the presentsubframe.

In FIG. 5C, SRSs 522, 524 are scheduled in both CCs. In this case, across-subframe interference may occur between an SRS in a presentsubframe and other channels in a future subframe, or between an SRS in apast subframe and other channels in a present subframe. A WTRU maytransmit SRS 522, 524 scheduled simultaneously on 2 CCs if the WTRU doesnot use (e.g., a PUSCH and a PUCCH are not mapped to) the next to lastsymbol 528 in the current subframe (subframe i) of the less advanced CCand the WTRU does not use (e.g., a PUSCH and a PUCCH are not mapped to)the first symbol 526 in the next subframe (subframe i+1) of the moreadvanced CC.

In FIGS. 5A-5C, two CCs are used just as an example and the embodimentsare applicable to the case where more than two CCs are active for theWTRU. In that case, the WTRU may determine whether to transmit an SRSbased on the scheduled transmissions and UL timing relationships of morethan one other CC.

In another embodiment, a WTRU may avoid using the additional symbols(horizontally crosshatched symbols 506, 516, 526, 528 in FIGS. 5A-5C) toallow the scheduled SRSs to be transmitted. The WTRU may avoid thediagonally crosshatched symbols 504, 516 in FIGS. 5A-5C to allow thescheduled SRS to be transmitted in the same CC as is the PUSCH or PUCCH.

In another embodiment, additional transmission formats may be defined.For example, a shortened PUSCH and/or PUCCH format that does not use thelast 2 symbols in the subframe, a shortened PUSCH and/or PUCCH formatthat does not use the first symbol in the subframe, and/or a shortenedPUSCH and/or PUCCH format that does not use both the first and lastsymbols in a subframe may be defined.

The WTRU may use one or more of the shortened formats based on anindication from the network as to whether the use of one or more suchshortened formats are allowed or an indication from the network that theWTRU should use one or more of the shortened formats. It may also bebased on the timing relationship, e.g., the WTRU's UL timingrelationship, between the CCs.

The WTRU may maintain two states (a first state of no TA difference anda second state of less than one symbol TA difference), and implement anyone of the embodiments disclosed above for transmissions of an SRS andother channels based on the state.

The embodiments disclosed above may be extended to the case where the TAdifference is greater than one symbol, for example in the range of 1-2symbols. FIGS. 6A-6C show examples of SRS and other channeltransmissions in case of TA difference of more than one symbol.

In FIG. 6A, an SRS 602 is scheduled in a more advanced CC. The WTRU maytransmit the scheduled SRS 602 for a given CC in subframe i if a PUSCHor a PUCCH is not mapped to both the second and third last symbols 604,606 of another CC (less advanced CC) in subframe i. The WTRU may dropthe scheduled SRS 602 for a given CC in subframe i if a PUSCH or a PUCCHis mapped to the second or third last symbols 604, 606 of another CC(less advanced CC) in subframe i.

In FIG. 6B, an SRS 612 is scheduled in a less advanced CC. In this case,a cross-subframe interference may occur between SRS in a presentsubframe and other channels in a future subframe. The WTRU may transmita scheduled SRS 612 for a given CC in subframe i if a PUSCH or a PUCCHis not mapped to both the first and second symbols 614, 616 in subframei+1 of another CC (more advanced CC). The WTRU may drop a scheduled SRS612 for a given CC in subframe i if a PUSCH or a PUCCH is mapped to thefirst or second symbol 614, 616 of another CC (more advanced CC) insubframe i+1.

In FIG. 6C, SRSs 622, 624 are scheduled in both CCs. In this case, across-subframe interference may occur between an SRS in a presentsubframe and other channels in a future subframe, or between an SRS in apast subframe and other channels in a present subframe. A WTRU maytransmit an SRS 622, 624 scheduled simultaneously on 2 CCs if the WTRUdoes not use (e.g., a PUSCH and a PUCCH are not mapped to) the two lastsymbols 630, 632 in the current subframe (subframe i) of the lessadvanced CC and the WTRU does not use (e.g., a PUSCH and a PUCCH are notmapped to) the first two symbols 626, 628 in the next subframe (subframei+1) of the more advanced CC.

In the above embodiments, the WTRU may maintain three states (e.g., afirst state of no TA difference, a second state of less than one symbolTA difference, and a third state of more than one symbol TA difference),and implement any one of the embodiments disclosed above fortransmissions of SRS and other channels based on the state.

In another embodiment, an SRS may be included at the start, rather thanat the end, of a subframe. FIG. 7 shows an example of cross-subframeconflicts for the case of SRS being at the front of a subframe. In acase where an SRS is in a less advanced TAG, a PUSCH or a PUCCH in thepresent subframe may conflict with an SRS 702 in the present subframe,and an SRS 704 in the future subframe may conflict with a PUSCH or aPUCCH in the future subframe. In a case where an SRS is in amore-advanced TAG, a PUSCH or a PUCCH in the past subframe may conflictwith an SRS 706 in the present subframe, and an SRS 708 in the futuresubframe may conflict with a PUSCH or a PUCCH in the present subframe.

The WTRU may not transmit an SRS to avoid the cross-subframe conflict,as the WTRU may have knowledge while processing the present subframe.For example, for the present subframe, the WTRU may decide to nottransmit an SRS because it may conflict with a PUSCH or a PUCCH in thepast subframe, and the WTRU may know about the channels in the pastsubframe at this decision point. In addition, in processing a PUSCHand/or a PUCCH in the present subframe, at that point in time the WTRUmay have knowledge of the SRS in the future subframe, and may puncture aPUSCH and/or shorten a PUCCH in the present subframe to accommodate theSRS in the future subframe.

With an SRS at the front of a subframe, the first (or first two)symbol(s) of a PUSCH may need to be punctured, rather than the lastsymbol, and a shortened PUCCH may start after SRS and end at the end ofthe subframe, rather than start at the start of the subframe, and end atthe next-to-last symbol.

In another embodiment, in order to avoid cross-subframe conflicts, anSRS may be included in the middle, (e.g., not the first or last symbol),of a subframe. FIG. 8 shows an example of an SRS 802, 804 included inthe middle of subframe. So long as the UL timing difference is on theorder of less than half of a subframe, there may be no cross-subframeconflicts whether the SRS is included in the more or less advanced TAG.With an SRS in the middle of a subframe, one (or two) PUSCH symbol(s)may need to be punctured towards the middle of the subframe, and ashortened PUCCH may be split around each side of SRS.

Embodiments disclosed above may be applied in one or more of thefollowing cases: (1) when a WTRU is operating with intra-band CA (it maybe limited to the case where the WTRU has at least 2 activated UL CCs),(2) when a WTRU is operating with inter-band CA (it may be limited tothe case where the WTRU has activated UL CCs in more than one band), (3)when a WTRU is operating with two or more independently controlled TAloops (e.g., the WTRU has at least two TAGs), or (4) when a WTRU isspecifically instructed by the eNB to apply the embodiments, (e.g., viaRRC or other signaling).

The embodiments disclosed above for SRS and other UL transmissions maybe applied always or when one or more of the above conditions (1)-(4) istrue. Alternatively, the embodiments above may be applied adaptively,for example, when one of the conditions (1)-(4) above is true and thedifference between the largest and smallest applied TA, (e.g., thelength of the overlapping portion, the TA difference, or the UL timingdifference), is greater than a threshold.

The embodiments may not be applied, for example even when the aboveconditions are true, if the difference used for the decision is lessthan a threshold. Hysteresis may be employed, (e.g., two differentthresholds may be used, one for starting to use these embodiments, andanother for stopping the use of these embodiments). The embodiments mayor may not be applied after signaling the condition warranting applyingor not applying the embodiments, starting at a certain subframe such assubframe k+4 after reporting the condition at subframe k. Theembodiments may or may not be applied after signaling the conditionwarranting applying or not applying the embodiments, starting at acertain subframe such as subframe k+4 after the WTRU receives a HARQ ACKof the report at subframe k.

When comparing a TA (or UL timing) difference to a threshold, themagnitude of the difference may be what is relevant, (e.g., it may notmatter which CC is more or less advanced).

For proper UL communications, the eNB may need to be aware of the rulesthe WTRU applied to its UL transmissions such as the rules the WTRUapplied for simultaneous SRS and other channel transmissions. In orderfor the eNB to know whether the embodiments are or are not used in anygiven subframe, the eNB may calculate or infer the TA (or UL timing)difference in the WTRU.

For the case of the WTRU using one common DL timing reference, the WTRUand the eNB may calculate or infer the maximum, (e.g., the largestamongst the CCs), TA difference in the WTRU as a difference betweenRx-Tx time difference measurement in each CC. The maximum TA differencemay be computed as follows:

ΔTAps=(TAp−TAs),  Equation (15)

where TAp may be the Rx-Tx time difference measurement for one cell,(e.g., PCell), and TAs may be the Rx-Tx time difference measurement foranother cell, (e.g., an SCell). The WTRU may report this measurement forone or more cells to the eNB where the report (e.g., report parameters,report contents, and the like) may be based on signaling (e.g.,measurement configuration) from the eNB.

For the case of the WTRU using different DL timing references for two ormore CCs, (e.g., PCell and one or more SCells), the WTRU and the eNB maycalculate or infer the maximum TA difference in the WTRU using the sameway as for the common DL reference case. Alternatively, the WTRU and theeNB may measure or determine the UL timing difference as the applied TAdifference minus the received DL reference timing difference. Forexample, the WTRU and the eNB may add a reference signal time difference(RSTD)-like measurement for each SCell or TAG which may provide the timedifference between the DL references of two cells or two TAGs (e.g.,ΔTREF=TREFp−TREFs), or compute UL timing difference as applied TAdifference (ΔTAps) minus the RSTD-like measurement (e.g.,(TAp−TAs)−(TREFp−TREFs)).

FIG. 9 shows an example of the use of measurements to determine TAdifference between two cells (e.g., PCell and SCell). The term ΔTAps maybe referred to as ΔTA, where it may be understood that the difference isbetween two CCs (e.g., primary and secondary CCs) in two different TAGs,or the two respective TAGs.

The WTRU may compute, treat, and/or report ΔTA as described above, or ina simpler way (e.g., ignoring the timing reference difference). The WTRUmay compute, treat, and/or report ΔTA as described, but instead of usingthe difference of actual timing advance applied to multiple CCs or TAGsusing the timing advance commands (e.g., accumulated timing advancecommands) received from the eNB and ignoring WTRU autonomous uplinktiming adjustments.

In another embodiment, a WTRU may calculate the TA or UL timingdifference and report it to the eNB. Such reports may be in conjunctionwith the WTRU starting or stopping special processing for large TAdifference (the timing reference may be the PCell), or just thereporting with the expectation that the network will use such reports toavoid large TA difference conflicting UL transmissions, for example, byscheduling policies in cell load balancing or by deactivating theproblematic SCell(s) in a TAG.

The WTRU may report one or more of the following, either periodically orevent-driven: the TA or UL timing of CCs or TAGs, the TA or UL timingdifference between two CCs or TAGs, the largest TA or UL timingdifference between any two CCs or TAGs, the UL timing differencerelative to PCell for any SCell TAG, the UL timing difference relativeto PCell for any SCell TAG configured to report such UL timingdifference (e.g., by RRC), the ordinal relative timing differencebetween TAGs (e.g., a list of TAGs from most advanced to least advancedor vice versa, or an indication of the most advanced TAG), an indicationwhen a TA or UL timing difference crosses a threshold (e.g., when thelargest TA or UL timing difference crosses a threshold), an indicationthat the WTRU has, is about to enter, or left the state of processinggiven large TA difference (this may be coupled with an indication orreport of TAG timing difference), or the like.

The event triggering the reporting may be activation of a first SCell ina TAG, (e.g., starting-up of an additional TAG that may start periodicreporting), or deactivation of the last SCell in a TAG, (e.g., stoppingof a TAG that may be followed by no more periodic reports). The reportsmay be by PHY signaling, MAC control element (CE), or RRC signaling. Thereports carried into a MAC CE may be sent together with the powerheadroom reporting for the concerned SCell TAG.

Embodiments for handling transmit power when there is UL timingdifference or TA difference are disclosed hereafter.

Conventional rules for a WTRU to avoid exceeding its maximum allowedoutput power, (e.g., its total configured maximum output power), whentransmitting on multiple CCs are typically predicated on the UL subframeboundaries of the CCs coinciding (e.g., exactly or nearly exactlycoinciding), for example assuming that there is no overlap (e.g.,adjacent subframe overlap) due to TA difference or no TA differenceamong CCs. However, when there is a TA difference, applying theconventional maximum power rules is not sufficient in all cases.

For example, when there is a TA difference among CCs, there may besimultaneous transmission of an SRS in one CC and a PUSCH and/or a PUCCHin another CC due to adjacent subframe overlap. For example, for a TAdifference of up to 60 μs, which may correspond to up to approximately84% of a symbol period in which an SRS may be transmitted, there may besimultaneous transmission of an SRS in one CC and a PUSCH and/or a PUCCHin another CC. This is not considered in the conventional maximum powerrules.

In another example, when there is a TA difference among CCs, a PUSCH inone CC may share power with a PUSCH in another CC that is nominally inan adjacent subframe. This is not considered in the conventional maximumpower rules or PUSCH scaling rules.

In embodiments described herein, maximum power may be replaced byconfigured maximum power, configured maximum output power, totalconfigured maximum output power, total configured maximum WTRU outputpower, and other like terminology. These and other like terms may beused interchangeably.

In one embodiment, for subframes without SRS, in case of no PUSCH withUCI, the PUSCH power may be scaled as follows:

$\begin{matrix}{{{\sum\limits_{c}{{w(i)} \cdot {f_{\Delta \; {TA}}( {{\hat{P}}_{{PUSCH},c}(i)} )}}} \leq ( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)}} )},} & {{Equation}\mspace{14mu} (16)}\end{matrix}$

where f_(ΔTA) is a function of multiple variables, where each of thevariables may be the nominal channel power in the current and adjacentsubframes. For example, f_(ΔTA) may be as follows:

ƒ_(ΔTA)({circumflex over (P)} _(PUSCH,c)(i))=max({circumflex over (P)}_(PUSCH,c)(i),{circumflex over (P)} _(PUSCH,c)(j)),  Equation (17)

where i is the current (or present) subframe (i.e., the one for whichthe powers are being computed), j=i−1 for the CC with less TA (or lessadvanced UL timing), and j=i+1 for the CC with more TA (or more advancedUL timing). Instead of the max(x,y) function in the above example, adifferent function, for example, a weighted average of PUSCH power ineach of the two subframes may be employed. Such weighting may be afunction of the TA (or UL timing) difference between the two CCs, forexample:

$\begin{matrix}{{{f_{\Delta \; {TA}}( {{\hat{P}}_{{PUSCH},c}(i)} )} = {{( {1 - \frac{\Delta \; {TA}}{1000}} ) \cdot {{\hat{P}}_{{PUSCH},c}(i)}} + {( \frac{\Delta \; {TA}}{1000} ) \cdot ( {{\hat{P}}_{{PUSCH},c}(j)} )}}},} & {{Equation}\mspace{14mu} (18)}\end{matrix}$

where ΔTA is the TA difference in microseconds.

Any or all power terms, (for example, {circumflex over(P)}_(PUSCH,c)(i), {circumflex over (P)}_(PUCCH)(i), or {circumflex over(P)}_(CMAX)(i)), in any of the embodiments disclosed herein may bereplaced with a function ƒ_(ΔTA)(•) of such term in any or all of thepower control formulas.

In case a PUSCH and/or a PUCCH overlaps with an SRS because of UL timingdifference, the SRS may be adjusted or scaled, for example to avoidexceeding the maximum allowed power, (e.g., the WTRU total configuredmaximum output power).

In case where an SRS is in the more advanced CC, (e.g., as shown in FIG.5A), if there is no transmission in the diagonally cross hatched symbol504 but there is a transmission in the horizontally cross hatched symbol506, an SRS power in that CC may be set by reducing the availabletransmit power in the CC, (e.g., P_(CMAX,c)), by some fraction of thepower of other channels in the CC. The fraction may be a function of theTA (or UL timing) difference between the CCs. For example, the SRS powermay be set as follows:

$\begin{matrix}{{{P_{{SRS},c}(i)} = {\min {\{ {{10\; {\log_{10}( {{{\hat{P}}_{{CMAX},c}(i)} - {\frac{\Delta \; {TA}}{T_{symb}}( {{{\hat{P}}_{PUCCH}(i)} + {\sum\limits_{c}{{\hat{P}}_{{PUSCH},c}(i)}}} )}} )}},{{P_{{SRS\_ OFFSET},c}(m)} + \ldots + {f_{c}(i)}}} \} \lbrack{dBm}\rbrack}}},} & {{Equation}\mspace{14mu} (19)}\end{matrix}$

where T_(symb) is the symbol period, (e.g., 83.3 μs for extended CP or71.4 μs for normal CP), and

P _(SRS) _(—) _(OFFSET,c)(m)+ . . . +ƒ_(c)(i)=P _(SRS) _(—)_(OFFSET,c)(m)+10 log₁₀(M _(SRS,c))+P _(O) _(—)_(PUSCH,c)(j)+α_(c)(j)·PL _(c)+ƒ_(c)(i).  Equation (20)

It should be noted that TA and ΔTA may be replaced by UL timing and ULtiming difference, respectively in any of the embodiments disclosedherein.

For the case of transmission in both the horizontally and diagonallycross hatched symbols 504, 506 in FIG. 5A, the SRS power may be set asfollows:

$\begin{matrix}{{P_{{SRS},c}(i)} = {\min {{\{ {{10\; {\log_{10}( {{{\hat{P}}_{{CMAX},c}(i)} - ( {{{\hat{P}}_{PUCCH}(i)} + {\sum\limits_{c}{{\hat{P}}_{{PUSCH},c}(i)}}} )} )}},{{P_{{SRS\_ OFFSET},c}(m)} + \ldots + {f_{c}(i)}}} \} \lbrack{dBm}\rbrack}.}}} & {{Equation}\mspace{14mu} (21)}\end{matrix}$

In case where an SRS is in the less advanced CC, (e.g., as shown in FIG.5B), if there is no transmission in the diagonally cross hatched symbol514 but there is a transmission in the horizontally cross hatched symbol516, the SRS power may be set as follows:

$\begin{matrix}{{{P_{{SRS},c}(i)} = {\min {\{ {{10\; {\log_{10}( {{{\hat{P}}_{{CMAX},c}(i)} - {\frac{\Delta \; {TA}}{T_{symb}}( {{{\hat{P}}_{PUCCH}(j)} + {\sum\limits_{c}{{\hat{P}}_{{PUSCH},c}(j)}}} )}} )}},{{P_{{SRS\_ OFFSET},c}(m)} + \ldots + {f_{c}(i)}}} \} \lbrack{dBm}\rbrack}}},} & {{Equation}\mspace{14mu} (22)}\end{matrix}$

where j=i+1.

For the case of transmission in both the horizontally and diagonallycross hatched symbols 514, 516, the SRS power may be set as follows:

$\begin{matrix}{{P_{{SRS},c}(i)} = {\min \{ {10\mspace{11mu} {{{\log_{10}( {{{{\hat{P}}_{{CMAX},c}(i)} - {\max ( {{\frac{\Delta \; {TA}}{T_{symb}}( {{{\hat{P}}_{PUCCH}(j)} + {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c}(j)}}} )}, \quad{( {1 - \frac{\Delta \; {TA}}{T_{symb}}} )( {{{\hat{P}}_{PUCCH}(i)} + {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c}(i)}}} )} )} )}},{{P_{{{SRS}\; \_ \; {OFFSET}},c}(m)} + \ldots + {f_{c}(i)}}} \}}\mspace{14mu}\lbrack {{dB}\; m} \rbrack}.}} }} & {{Equation}\mspace{14mu} (23)}\end{matrix}$

In case where an SRS is transmitted in both CCs, (e.g., as shown in FIG.5C), if there is a transmission in the horizontally cross hatchedsymbols 526, 528, the SRS power per CC may be set per the aboveembodiments for each SRS in the more and less advanced CC, respectively,and then scaled as follows:

$\begin{matrix}{{\sum\limits_{c}\; {{w(i)} \cdot {{\hat{P}}_{{SRS},c}(i)}}} \leq {{{\hat{P}}_{CMAX}(i)} - {\frac{\Delta \; {TA}}{T_{symb}}{{\max ( {{{{\hat{P}}_{PUCCH}(i)} + {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c}(i)}}},{{{\hat{P}}_{PUCCH}(j)} + {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c}(j)}}}} )}.}}}} & {{Equation}\mspace{14mu} (24)}\end{matrix}$

The embodiments disclosed above may reflect an SRS having lower prioritythan a PUCCH or a PUSCH.

In the above equations, the factors

${{\frac{\Delta \; {TA}}{T_{symb}}\mspace{14mu} {and}\mspace{14mu} 1} - \frac{\Delta \; {TA}}{T_{symb}}},$

intended as weighting factors as a function of the TA difference betweenthe CCs, are examples and different factors may be employed.

Allowing for simultaneous transmissions of a PRACH and other channel(s),the above inequality may be modified as follows:

$\begin{matrix}{{{\sum\limits_{c}\; {{w(i)} \cdot {{\hat{P}}_{{SRS},c}(i)}}} \leq {{{\hat{P}}_{CMAX}(i)} - {\frac{\Delta \; {TA}}{T_{symb}}{\max \begin{pmatrix}{{{{\hat{P}}_{PRACH}^{SRS}(i)} + {{\hat{P}}_{PUCCH}(i)} + {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c}(i)}}},} \\{{{\hat{P}}_{PRACH}(j)} + {{\hat{P}}_{PUCCH}(j)} + {\sum{{\hat{P}}_{{PUSCH},c}(j)}}}\end{pmatrix}}}}},} & {{Equation}\mspace{14mu} (25)}\end{matrix}$

where {circumflex over (P)}_(PRACH)(i) may be the linear equivalent ofP_(PRACH) in subframe i, {circumflex over (P)}_(PRACH) ^(SRS)(i) may be{circumflex over (P)}_(PRACH)(i) during the SRS symbol in subframe i(which may be zero in the last or only subframe of a preamble).

Alternatively, the SRS may be dropped rather than scaling the SRS whenΣ_(c){circle around (P)}_(SRS, c) would or is to exceed the availablepower.

In case where an SRS and a PUCCH and/or PUSCH may be scheduled in apresent subframe, if it has been determined to use a shortened PUCCHformat and/or to shorten the PUSCH to allow transmission of thescheduled SRS, but subsequently the WTRU, being power-limited due topartial overlap of an SRS in the present subframe and a PUSCH, a PUCCH,or a PRACH in the next subframe, decides not to transmit the SRS in thepresent subframe, the WTRU may restore the PUCCH and/or the PUSCH in thepresent subframe to their original format and/or size. Alternatively,the WTRU may not restore the PUCCH and/or the PUSCH.

For carrier aggregation (CA) with UL serving cells, the WTRU maydetermine (or set) the total configured maximum WTRU output powerP_(CMAX) within a lower and upper bound as follows:

P _(CMAX) _(—) _(L) _(—) _(CA) ≦P _(CMAX) ≦P _(CMAX) _(—) _(H) _(—)_(CA).  Equation (26)

In one embodiment, a WTRU may avoid exceeding the maximum power whenthere is a TA (or UL timing) difference by adding an additional powerbackoff term (e.g., an MPR-like term) to the lower limit of theconfigured maximum WTRU output power for CA. This may, in effect, betreating the power from the past subframe that is overlapping into thepresent subframe as a higher priority by reducing, (e.g., backing off),the transmit power available to the channels scheduled for the currentsubframe.

FIG. 10 shows an example in which there may be interference between thepast subframe to the present subframe. As shown in FIG. 10, a WTRU mayknow how much interference TAG1's past subframe may cause to TAG2'spresent subframe (1002) and how much interference TAG2's presentsubframe may cause to TAG1's present subframe (1004), but may not knowhow much interference TAG2's future subframe may cause to TAG1's presentsubframe (1006), which may be ignored.

For the present subframe, the transmit power of the past subframe may beknown, whereas the transmit power in the future subframe may not beknown. As the transmit power in the past subframe has already beendetermined, the WTRU may backoff the maximum transmit power available inthe present subframe for the present subframe to accommodate transmitpower in the past subframe that overlaps to the present subframe. Thepower overlapping from the past subframe into the present subframe,averaged out over the entire present subframe, may be at most a smallfraction of P_(CMAX)(i), and any adverse effects of the overlap (e.g.,excessive adjacent channel or out-of-band interference) which may begenerated by the WTRU during the relatively brief overlap period may beaveraged out over the subframe period.

For any given CC, the interfering power from an overlapping subframe maybe from a different CC. Therefore, instead of applying a backoff toP_(CMAX,c)(i) (e.g., the configured maximum WTRU output power for aserving cell c for subframe i), a backoff may be applied to the WTRU asa whole, as a factor for reducing P_(CMAX)(i) (e.g., the totalconfigured maximum WTRU output power for subframe i). For example, thebackoff may be applied to the lower limit of P_(CMAX)(i), which may alsobe referred to herein as simply P_(CMAX). For example, for carrieraggregation such as inter-band carrier aggregation, (e.g., with up toone serving cell per operating band), the lower limit of P_(CMAX),P_(CMAX) _(—) _(L) _(—) _(CA), may include a new power backoff term(that may be referred to as TA maximum power reduction (T-MPR) or tmprwhere T-MPR may be a value in dB and tmpr may be the linear value ofT-MPR) or alternatively, one or more terms may be included in theequation used to determine P_(CMAX) _(—) _(L) _(—) _(CA). For example,for inter-band CA or non-contiguous intra-band CA, P_(CMAX) _(—) _(L)_(—) _(CA) may be determined as follows:

P _(CMAX) _(—) _(L) _(—) _(CA)=MIN{10 log₁₀ ΣMIN[p _(EMAX,c)/(Δt_(C,c)),p _(PowerClass)/(mpr _(c) ·a-mpr _(c) ·Δt _(C,c) ·Δt _(IB,c)),p_(PowerClass)/(pmpr _(c) ·Δt _(C,c)),p _(PowerClass)/(tmpr·Δt _(C,c))],P_(PowerClass)};  Equation (27)

or alternatively as follows:

P _(CMAX) _(—) _(L) _(—) _(CA)=MIN{10 log₁₀ MIN[p _(EMAX,c)/(Δt_(C,c)),p _(PowerClass)/(mpr _(c) ·a-mpr _(c) ·tmpr·Δt _(C,c) ·Δt_(IB,c)),p _(PowerClass)/(pmpr _(c) ·Δt _(C,c))],P_(PowerClass)}.  Equation (28)

Alternatively, the backoff may be included, (e.g., for intra-bandcarrier aggregation, or intra-band contiguous CA), in the lower limit ofP_(CMAX) as follows:

P _(CMAX) _(—) _(L) _(—) _(CA)=MIN{10 log₁₀ p _(EMAX,c) −ΔT _(C) ,P_(PowerClass)−MAX(MPR+A-MPR+T-MPR,P-MPR)−ΔT _(C)}.  Equation (29)

In any of the embodiments above, the T-MPR (or tmpr) may be the same forall CCs or may have a CC-specific value.

In another embodiment, P_(CMAX) may be initially determined withoutconsideration for the overlap and then a backoff may be applied to theP_(CMAX) based on the overlap, as follows:

P _(CMAX) accounting for overlap=(P _(CMAX) excludingoverlap−T-MPR),  Equation (30)

Using P_(CMAX)(i) to represent P_(CMAX) excluding overlap in subframe iand F_(CMAXov)(i) to represent P_(CMAX) accounting for overlap insubframe i, P_(CMAX) accounting for overlap in subframe i may be writtenas follows:

P _(CMAXov)(i)=P _(CMAX)(i)−T-MPR, or  Equation (31)

P _(CMAXov)(i)=P _(CMAX)(i)−T-MPR(i).  Equation (32)

In linear form, it may be written as follows:

p _(CMAXov)(i)=p _(CMAX)(i)/tmpr, or  Equation (33)

p _(CMAXov)(i)=p _(CMAX)(i)/tmpr(i).  Equation (34)

In this case, determination of exceeding maximum power and/or scalingfor power control may be done with respect to P_(CMAXov)(i) instead ofP_(CMAX)(i) (or p_(CMAXov)(i) instead of p_(CMAX)(i)).

In another embodiment, P_(CMAX) _(—) _(L) _(—) _(CA) may be determinedwithout consideration for the overlap and then the backoff may beapplied as follows:

P _(CMAX) _(—) _(L) _(—) _(CA) accounting for overlap=(P _(CMAX) _(—)_(L) _(—) _(CA) excluding overlap−T-MPR).  Equation (35)

P_(CMAX) _(—) _(L) _(—) _(CA) (e.g., for inter-band CA) may becalculated as follows:

P _(CMAX) _(—) _(L) _(—) _(CA)=MIN{10 log₁₀ ΣMIN[p _(EMAX,c)/(Δt_(C,c)),p _(PowerClass)/(mpr _(c) ·a-mpr _(c) ·Δt _(C,c) ·Δt _(IB,c)),p_(PowerClass)/(pmpr _(c) ·Δt _(C,c))],P _(PowerClass) }−T-MPR.  Equation(36)

Alternatively, P_(CMAX) _(—) _(L) _(—) _(CA) (e.g., for intra-band CA),may be calculated as follows:

P _(CMAX) _(—) _(L) _(—) _(CA)=MIN{10 log₁₀ Σp _(EMAX,c) −ΔT _(C) ,P_(PowerClass)−MAX(MPR+A-MPR,P-MPR)−ΔT _(C) }−T-MPR.  Equation (37)

Addition of the additional backoff T-MPR which may be in dB form (ortmpr which may be in linear form) may allow a WTRU to lower the lowerlimit of the configured maximum output power or the configured maximumoutput power itself to avoid the effect of TA (or UL timing) differencewhich may cause the WTRU to exceed the configured maximum output powerduring a given subframe or a given measurement period (e.g., 1 ms).

In another embodiment, the additional backoff may be applied to both thelower limit and upper limit of P_(CMAX)(i). For example, for intra-bandCA and/or inter-band carrier aggregation (e.g., with up to one servingcell c per operating band), P_(CMAX) _(—) _(H) _(—) _(CA), may becalculated as one of the following:

P _(CMAX) _(—) _(H) _(—) _(CA)=MIN{10 log₁₀ Σp _(EMAX,c) ,p_(PowerClass) /tmpr};  Equation (38)

P _(CMAX) _(—) _(H) _(—) _(CA)=MIN{10 log₁₀ ΣMIN[p _(EMAX,c) ,p_(PowerClass) /pmpr _(c) ],p _(PowerClass)/tmpr};  Equation (39)

P _(CMAX) _(—) _(H) _(—) _(CA)=MIN{10 log₁₀ Σp _(EMAX,c) ,P_(PowerClass) }−T-MPR; or  Equation (40)

P _(CMAX) _(—) _(H) _(—) _(CA)=MIN{10 log₁₀ ΣMIN[p _(EMAX,c) ,p_(PowerClass) /pmpr _(c) ]}−T-MPR.  Equation (41)

The T-MPR may be a power reduction value or a power reduction allowancesuch that the WTRU may choose an actual reduction value less than orequal to that allowance value.

The amount of T-MPR allowed or actual power backoff may be either 0 dB,a fixed value, or a value from a set which may include more than onevalue, (e.g., 0 for small ΔTA and some value for large ΔTA). The T-MPRmay be selected by a WTRU, for example from a list. The list may bespecified or provided by the network to the WTRU. The network may signalto the WTRU, (e.g., via physical layer signaling, MAC CE, RRC signaling,or the like), an index into the list to use. Alternatively, the WTRU mayautonomously determine the index, for example as a function of ΔTA.Example of fixed values or lists are {0,1} dB, or {0, 0.5, 1.0} dB.

The WTRU may determine the T-MPR as a function of the transmit power inthe previous subframe, as well as, or instead of, a function of ΔTA. Forexample, for any given ΔTA, less transmit power in subframe i−1 mayresult in less T-MPR in subframe i.

The T-MPR for the present subframe may be determined as a function ofone or more of the following: the number of TAGs with activated CCs withconfigured UL in one or more of the past, present, and future subframes,the number of TAGs with scheduled UL transmission in one or more of thepast, present, and future subframes, or the number of bands of the CCswith UL transmission in one or more of the past, present, and futuresubframes.

The T-MPR may be applicable (e.g., only applicable) in subframes with apotential overlap, (e.g., when the WTRU is scheduled to transmit in theUL in at least one TAG in the present subframe and a TAG other than thatTAG in the past or future subframe).

The T-MPR may be a function of one or more of the ΔTAs (or UL timingdifferences) between the CCs in different TAGs. For example, the T-MPRmay be a function of the largest ΔTA (or UL timing difference) betweeneach pair of TAGs. This may be applicable to TAGs with UL transmissionin one or more of the present, past, or future subframes. A larger ΔTA(or UL timing difference) may result in, or correspond to, a largerT-MPR.

The T-MPR may be a function of the amount of overlap, for example afunction of the overlap time divided by the subframe time or the timefor the symbols (which may exclude the CP time).

The WTRU may determine the T-MPR for the present subframe as a functionof the transmit power in the past subframe and/or the transmit power inthe future subframe. The transmit power in the past subframe may be theactually determined transmit power which may be after any scaling isdone and may or may not account for the T-MPR determined for thatsubframe. The transmit power in the future subframe may be thecalculated transmit power for that subframe which may be after anyscaling and may or may not account for the T-MPR for that subframe.

The WTRU may determine the T-MPR for the present subframe as a functionof P_(CMAX) in the past subframe and/or P_(CMAX) in the future subframe.P_(CMAX) used for the past subframe may or may not account for T-MPRdetermined for that subframe. P_(CMAX) for the future subframe may ormay not account for T-MPR for that subframe.

After the WTRU determines the T-MPR, the WTRU may determine the actualbackoff value to use. The WTRU may determine the T-MPR allowance and/orthe actual backoff on a subframe by subframe basis.

In the above embodiments, ΔTA may be replaced with UL timing difference.

Determination of the PUCCH transmit power for subframe i and the scalingrules for the PUSCH transmit power may be based on the assumption thatP_(CMAX,c)(i) for the PCell is not greater than P_(CMAX)(i). However,with the backoff of T-MPR applied to P_(CMAX)(i) but not toP_(CMAX,c)(i) of the PCell, this assumption may not necessarily be true.To compute P_(PUCCH)(i) while allowing for P_(CMAX,c)(i) for the PCellto be greater than P_(CMAX)(i), the WTRU may determine PUCCH power,e.g., in a first step in scaling, as follows:

{circumflex over (P)} _(PUCCH)(i)=min({circumflex over (P)}_(PUCCH)(i),{circumflex over (P)} _(CMAX)(i)).  Equation (42)

Alternatively, PUCCH power may be determined as follows:

$\begin{matrix}{{{P_{PUCCH}(i)} = {\min \begin{Bmatrix}{\min ( {{P_{CMAX}(i)},{P_{{CMAX},c}(i)}} )} \\{P_{0\_ \; {PUCCH}} + {PL}_{c} + {h( {n_{CQI},{n_{{HARQ},}n_{SR}}} )} +} \\{{\Delta_{F\; \_ \; {PUCCH}}(F)} + {\Delta_{TxD}( F^{\prime} )} + {g(i)}}\end{Bmatrix}}},} & {{Equation}\mspace{14mu} (43)}\end{matrix}$

where c is the CC on which PUCCH may be transmitted, e.g., the PCell.

After determining P_(PUCCH)(i), the following maybe performed:

{circumflex over (P)} _(PUCCH)(i)=min({circumflex over (P)}_(PUCCH)(i),{circumflex over (P)} _(MAX)(i)).  Equation (44)

P_(CMAXov)(i) may replace P_(CMAX)(i) in the equations above. The linearequivalent of P_(CMAXov)(i) may replace the linear equivalent ofP_(CMAX)(i) in the equations above.

A PRACH transmission may last for some period of time, denoted asT_(CP)+T_(SEQ), depending on the PRACH preamble format. Such periods arenominally one to three subframes. During the last subframe of atwo-subframe or three-subframe transmission, or the single subframe of aone-subframe PRACH transmission, the PRACH transmission may end beforethe end of the last or the single subframe. The number of full subframesand the unused portion of the last or the single subframe for eachpreamble format may, for example, be as given in Table 1. For example, aPRACH preamble format 1 transmission may last for one full subframefollowed by approximately 48% of a second subframe.

TABLE 1 Length of Number Empty space at PRACH preamble of full end oflast preamble including sub- subframe of format T_(CP) (Ts) T_(SEQ) (Ts)CP, μs frames preamble, μs 0 3168 24576 903.12 0 96.88 1 21024 245761484.38 1 515.62 2 6240 2 × 24576 1803.13 1 196.87 3 21024 2 × 245762284.38 2 715.62 4 (TDD) 448  4096 147.92 0 852.08

A PRACH in the past subframe may or may not have any effect needed to beincluded in determining the T-MPR for the present subframe. A PRACHtransmission may occupy the entire past subframe if it is not the lastsubframe of a multi-subframe PRACH, (e.g., PRACH preamble format 1, 2,or 3). In this case, the impact of the PRACH in the past subframe may besimilar to that of a PUSCH and/or a PUCCH in the past subframe. However,for the case of the past subframe being either the single subframe(e.g., in case of PRACH preamble format 0 or 4) or the last subframe(e.g., in case of PRACH preamble format 1, 2, or 3) of the PRACHtransmission, there may or may not be an overlap of the past PRACH intothe present subframe.

FIG. 11 shows an example of overlap of a PRACH in the past subframe intothe present subframe. In this example, ψ is length of the PRACHtransmission in the past subframe. ψ is mod(T_(CP)(•)+T_(SEQ)(•), 0.001)seconds for the last PRACH frame and 0.001 seconds for other PRACHframes. T_(CP)(•) is the length of the PRACH preamble CP part andT_(SEQ)(•) is the length of the PRACH preamble sequence part, and mod( )is the modulo operation. The fraction of the PRACH power in the pastsubframe that overlaps into the present subframe may be as follows:

Q(i)=max[0,TA _(c)(i)−TA _(j)(i)−ΔTREF_(c,p)(i)−(1−1000·ψ(i−1))]·({circumflex over (P)}_(PRACH)(i−1)),  Equation (45)

where p is the PCell in subframe i.

The WTRU may use the factor Q(i) to determine the impact of PRACH in thepast subframe on T-MPR for the present subframe.

Determination of the PRACH power for subframe i and the scaling rulesfor PUSCH transmit power may be based on the assumption thatP_(CMAX,c)(i) for the serving cell transmitting the PRACH is not greaterthan P_(CMAX)(i). However, with the backoff of T-MPR applied toP_(CMAX)(i) but not to P_(CMAX,c)(i) of the serving cell transmittingthe PRACH, this assumption may not necessarily be true. To computeP_(PRACH)(i) for serving cell c while allowing for P_(CMAX,c)(i) forsaid serving cell c being greater than P_(CMAX)(i), the WTRU maydetermine PRACH and PUCCH power based on priority rules as follows.

For the case of a PRACH having higher priority than a PUCCH, the WTRUmay determine the PRACH and PUCCH power as follows:

{circumflex over (P)} _(PRACH)(i)=min({circumflex over (P)}_(PRACH)(i),{circumflex over (P)} _(CMAX)(i)), and  Equation (46)

{circumflex over (P)} _(PUCCH,j)(i)=min({circumflex over (P)}_(PUCCH,j)(i),({circumflex over (P)} _(CMAX)(i)−{circumflex over (P)}_(PRACH)(i)).  Equation (47)

An alternative of equation (47) is:

{circumflex over (P)} _(PUCCH,j)(i)=min({circumflex over (P)}_(PUCCH,j)(i),({circumflex over (P)} _(CMAX)(i)−α_(PRACH)(i)·{circumflexover (P)} _(PRACH)(i))),  Equation (48)

where the factor α_(PRACH)(i) may account for the length of the PRACH insubframe i being less than the entire subframe, depending on the PRACHpreamble format. The factor may be, for example, the ratio of the lengthof the PRACH preamble in subframe i to the length of the subframe, orsome other value α′_(PRACH)(i), where 0<α_(PRACH)(i)<α_(PRACH)(i)<1. Forthe case of subframe i not being the last subframe of a PRACH preambleformat such as format 1, 2 or 3, the factor may be unity.

For the case of a PUCCH having a higher priority than a PRACH, the WTRUmay determine the PUCCH and PRACH power as follows:

{circumflex over (P)} _(PUCCH)(i)=min({circumflex over (P)}_(PUCCH)(i),{circumflex over (P)} _(CMAX)(i)), and  Equation (49)

{circumflex over (P)} _(PRACH)(i)=min({circumflex over (P)}_(PRACH)(i),({circumflex over (P)} _(CMAX)(i)−{circumflex over (P)}_(PUCCH)(i))).  Equation (50)

In another embodiment, the WTRU may compute P_(PRACH)(i) for servingcell c while allowing for P_(CMAX,c)(i) for the serving cell c beinggreater than P_(CMAX)(i). The WTRU may compute P_(PRACH)(i) as follows:

P _(PRACH)(i)=min(min(P _(CMAX)(i),P_(CMAX,c)(i)),PREAMBLE_RECEIVED_TARGET_POWER+PL_(c))  Equation (51)

where P_(CMAX,c)(i) may be the configured WTRU transmit power forsubframe i of the primary cell and PL_(c) may be the downlink pathlossestimate calculated in the WTRU for the primary cell.

If the total transmit power of the WTRU would or is to exceed{circumflex over (P)}_(CMAX)(i), the WTRU may differently scale{circumflex over (P)}_(PUSCH,c)(i) for the serving cell c in subframe isuch that the following condition is satisfied:

$\begin{matrix}{{\sum\limits_{c}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq {( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{a_{PRACH}(i)} \cdot {{\hat{P}}_{PRACH}(i)}}} ).}} & {{Equation}\mspace{14mu} (52)}\end{matrix}$

Alternatively, α_(PRACH)(i) may not be included. In case there is noPRACH transmission in subframe i, {circumflex over (P)}_(PRACH)(i)=0.

If the WTRU has a PUSCH transmission with UCI on serving cell j and aPUSCH transmission without UCI in any of the remaining serving cells,and the total transmit power of the WTRU would or is to exceed{circumflex over (P)}_(CMAX)(i), the WTRU may differently scale{circumflex over (P)}_(PUSCH,c)(i) for the serving cells without UCI insubframe i such that the following condition is satisfied:

$\begin{matrix}{{\sum\limits_{c \neq j}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq {( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUSCH},j}(i)} - {{a_{PRACH}(i)} \cdot {{\hat{P}}_{PRACH}(i)}}} ).}} & {{Equation}\mspace{14mu} (53)}\end{matrix}$

α_(PRACH)(i) may not be included, and in case there is no PRACHtransmission in subframe i, {circumflex over (P)}_(PRACH)(i)=0.

If the WTRU has a simultaneous PUCCH and PUSCH transmission with UCI onserving cell j and a PUSCH transmission without UCI in any of theremaining serving cells, and the total transmit power of the WTRU wouldor is to exceed P_(CMAX)(i), the WTRU may compute {circumflex over(P)}_(PUSCH,c)(i) as follows:

$\begin{matrix}{{{{\hat{P}}_{{PUSCH},j}(i)} = {\min ( {{{\hat{P}}_{{PUSCH},j}(i)},( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{a_{PRACH}(i)} \cdot {{\hat{P}}_{PRACH}(i)}}} )} )}},} & {{Equation}\mspace{14mu} (54)} \\{{\sum\limits_{c \neq j}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq {( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{a_{PRACH}(i)} \cdot {{\hat{P}}_{PRACH}(i)}} - {{\hat{P}}_{{PUSCH},j}(i)}} ).}} & {{Equatio}\; n\mspace{14mu} (55)}\end{matrix}$

α_(PRACH)(i) may not be included.

P_(CMAXov)(i) may replace P_(CMAX)(i) in the equations above. The linearequivalent of P_(CMAXov)(i) may replace the linear equivalent ofP_(CMAX)(i) in the equations above.

A WTRU may report a power headroom to the eNB. The WTRU may include anindication in the power headroom report that non-zero T-MPR has beenused. There may be one indication for the WTRU. Alternatively, there maybe one indication per TAG or per CC or per CC with real headroomincluded in the report.

The WTRU may include P_(CMAX)(i) in the power headroom report when theeNB may not be able to determine P_(CMAX)(i) itself, (e.g., from otherfactors such as from the P_(CMAX,c)(i) values included in the powerheadroom report).

The WTRU may include P_(CMAX)(i) in the power headroom report when oneor more of the following is true: (1) P_(CMAX)(i) does not equal one ormore of P_(CMAX,c)(i) values included in the power headroom report forexample for intra-band CA or contiguous intra-band CA; or (2)P_(CMAX)(i) does not equal the sum of the P_(CMAX,c)(i) values includedin the power headroom report (e.g., the sum may be capped byP_(PowerClass) for example for the case of inter-band CA ornon-contiguous intra-band CA).

The WTRU may include in the power headroom report an indication thatP_(CMAX)(i) is included in the power headroom report.

The WTRU may trigger a power headroom report when the actual backoff dueto overlap changes by more than a threshold. The trigger in a givensubframe may require real UL transmission (e.g., PUSCH, PUCCH, or PRACH)in more than one TAG in that subframe. The trigger in a given subframemay require an overlap condition between two or more TAGs in thatsubframe. The overlap condition may require UL transmission (which maybe one or more of PUSCH, PUCCH, or PRACH) in at least one TAG in thecurrent subframe and at least one other TAG in the previous and/or nextsubframe. The starting subframe for comparison may be the most recentsubframe in which a power headroom report was sent and the WTRU had realUL transmission in more than one TAG. The starting subframe forcomparison may be the most recent subframe in which a power headroomreport was sent and the WTRU had an overlap condition.

It should be noted that including P_(CMAX)(i) in the power headroomreport is not limited to the above cases related to the use of T-MPR.

In the above embodiments, P_(CMAX)(i) may be replaced by P_(CMAXov)(i)in one or more of the above power headroom reporting modifications.

In one embodiment, the WTRU may include P_(CMAX)(i) in the powerheadroom report (for example in the subframe or TTI i in which the powerheadroom report is to be transmitted) if one or more of the followingconditions is true:

P _(CMAX)(i)≠Σp _(CMAX,c)(i) when Σp _(CMAX,c)(i)<p _(PowerClass); or

p _(CMAX)(i)≠p _(PowerClass) when Σp _(CMAX,c)(i)>=p _(PowerClass).

A WTRU may not include P_(CMAX)(i) in the power headroom report if oneor more of the above conditions is not met.

In another embodiment, the WTRU may include P_(CMAX)(i) in the powerheadroom report (for example in the subframe or TTI i in which the powerheadroom report is to be transmitted) if the following is true:

p _(CMAX)(i)≠min[Σp _(CMAX,c)(i),p _(PowerClass)].

A WTRU may not include P_(CMAX)(i) in the power headroom report if thiscondition is not met.

The above embodiments may be applicable to inter-band CA and/ornon-contiguous intra-band CA. The above embodiments may be applicable toa power headroom report in a subframe or TTI in which the WTRU has realUL transmissions for at least two CCs that are in at least one ofdifferent bands, different clusters, different TAGs, and the like.

Σp_(CMAX,c)(i) in the above conditions may be the sum of theP_(CMAX,c)(i) values (or their linear equivalents) which may be one ormore of the P_(CMAX,c)(i) values included in the power headroom report,the P_(CMAX,c)(i) values in the power headroom report for activated CCswith UL transmissions (which may include PUSCH and/or PUCCHtransmissions and may not include PRACH and/or SRS transmissions) in thesubframe (or TTI) of the power headroom report, (e.g., subframe or TTIi), or the P_(CMAX,c)(i) values used in (e.g., used to cap) the powercalculations of the channels of the activated CCs with UL transmissions(which may include PUSCH and/or PUCCH transmissions and may not includePRACH and/or SRS transmissions) in the subframe (or TTI) of the powerheadroom report (PHR), (e.g., subframe or TTI i).

For the case of the PCell which may have both a Type 1 and a Type 2power headroom report, and may have a P_(CMAX,c)(i) value associatedwith each, the P_(CMAX,c)(i) value which may be used for the P_(CMAX,c)sum (e.g., Σp_(CMAX,c)(i)) may be one of the following: (1) theP_(CMAX,c)(i) value transmitted in the power headroom report for thePCell if only one is transmitted, (2) the P_(CMAX,c)(i) value associatedwith the Type 1 power headroom report if there is a PUSCH but no PUCCHtransmission on the PCell in the subframe in which the power headroomreport is to be transmitted, (3) the P_(CMAX,c)(i) value associated withthe Type 2 power headroom report if there is a PUCCH but no PUSCHtransmission on the PCell in the subframe in which the power headroomreport is to be transmitted, (4) the P_(CMAX,c)(i) value associated withthe Type 2 power headroom report if there are both PUCCH and PUSCHtransmissions on the PCell in the subframe in which the power headroomreport is to be transmitted, (alternatively, the P_(CMAX,c)(i) valueassociated with the Type 1 power headroom report may be used), or (5)the P_(CMAX,c)(i) value used for (e.g., used to cap) the powercalculations for the channels of the PCell in the subframe in which thepower headroom report is to be transmitted.

Instead of, or in addition to, applying a backoff to P_(CMAX)(i), abackoff may be applied on a per TAG basis to serving cells within a TAG.The power backoff may be denoted as T-MPRs and may be applied toP_(CMAX,c)(i) as follows:

P _(CMAX) _(—) _(L,c)=MIN{P _(EMAX,c) −ΔT _(C,c) ,P_(PowerClass)−MAX(MPR _(c) +A-MPR _(c) +ΔT _(IB,c) ,P-MPR _(c) ,T-MPR_(c))−ΔT _(C,c)};  Equation (56)

P _(CMAX) _(—) _(L,c)=MIN{P _(EMAX,c) −ΔT _(C,c) ,P_(PowerClass)−MAX(MPR _(c) +A-MPR _(c) +ΔT _(IB,c) ,T-MPR _(c) ,P-MPR_(c))−ΔT _(C,c)};  Equation (57)

P _(CMAX) _(—) _(L,c)=MIN{P _(EMAX,c) −ΔT _(C,c) ,P_(PowerClass)−MAX(MPR _(c) +A-MPR _(c) +ΔT _(IB,c) ,P-MPR _(c),)−T-MPR_(c) −ΔT _(C,c)}; or  Equation (58)

P _(CMAX) _(—) _(L,c)=MIN{P _(EMAX,c) −ΔT _(C,c) ,P_(PowerClass)−MAX(MPR _(c) +A-MPR _(c) +ΔT _(IB,c) ,P-MPR _(c),)−ΔT_(C,c)};−T-MPR _(c).  Equation (59)

In addition to the above, the following may be applied.

P _(CMAX) _(—) _(H,c)=MIN{P _(EMAX,c) ,P _(PowerClass) ,P _(PowerClass)−T-MPR _(c)};  Equation (60)

P _(CMAX) _(—) _(H,c)=MIN{P _(EMAX,c) ,P _(PowerClass) −T-MPR _(c)};or  Equation (61)

P _(CMAX) _(—) _(H,c)=MIN{P _(EMAX,c) ,P _(PowerClass) }−T-MPR_(c).  Equation (62)

T-MPR may be applied to serving cells in the more advanced TAG, orapplied to serving cells in the less advanced TAG.

T-MPR and/or T-MPRs, (e.g., backoff from P_(PowerClass)), may be appliedfor a short period of time, (for example, for the duration of SRS, forthe duration of the overlap period between TAGs, or for the overlapperiod plus transient periods).

The WTRU may create guard symbols between subframes to avoid overlappingchannels, (e.g., in a present subframe in a more advanced TAG). The WTRUmay puncture a PUSCH and/or shorten a PUCCH, and thus may not transmit aPUSCH and/or a PUCCH in that TAG, for example, for the first one or twosymbols of the present subframe. FIG. 12 shows an example of a guardsymbol 1202 included in the present subframe in a more advanced CC.

Guard symbols may be used if any condition disclosed above for droppingthe SRS in an overlapping region is satisfied. Alternatively oradditionally, the WTRU may include the guard symbols when there is atransmission in the less advanced TAG in the past subframe and atransmission in the more advanced TAG in the present subframe, and/or ifthe sum of transmit powers would or is to exceed P_(CMAX)(i) for thepresent subframe.

The guard symbols may be the first and last symbols of a subframe in anSCell in an sTAG. Alternatively, the guard symbols may be the firstsymbol of a subframe in an SCell in an sTAG if there is a transmissionin the PCell or any SCell in the pTAG in the previous subframe thatuses, or is scheduled to use, the last symbol of that subframe. Anexample of a transmission that is scheduled to use, but does not use,the last symbol in a subframe is an SRS that is not transmitted, forexample, due to transmit power constraint. Alternatively, the guardsymbol may be the last symbol of a subframe in an SCell in an sTAG ifthere is a transmission in the PCell or any SCell in the pTAG in thenext subframe. In these cases, the WTRU and/or the eNB may not need toknow or determine which CC or TAG is more or less advanced.

For constant PRACH power over the entire PRACH preamble, a PRACHpreamble transmission power, P_(PRACH), may be determined as follows:

P _(PRACH)=min{P _(CMAX,c)(j),PREAMBLE_RECEIVED_TARGET_POWER+PL_(c)),  Equation (63)

where subframe j may be the first subframe of the preamble,P_(CMAX,c)(j) may be the configured WTRU transmit power for subframe jof serving cell c and PL_(c) may be the downlink pathloss estimatecalculated in the WTRU for serving cell c. P_(PRACH) may be in dBm.

Equation (63) may be expressed as follows:

P _(PRACH)(i)=min{P _(CMAX,c)(j),PREAMBLE_RECEIVED_TARGET_POWER+PL_(c)),  Equation (64)

where subframe i may be any subframe of the preamble, j may be the firstsubframe of the preamble, P_(CMAX,c)(j) may be the configured WTRUtransmit power for subframe j of the serving cell c, and PL_(c) may bethe downlink pathloss estimate calculated in the WTRU for the servingcell c. P_(PRACH)(i) may be in dBm.

After determining P_(PRACH) or P_(PRACH)(i), additional processing maybe performed to allow for P_(CMAX)<P_(CMAX,c), which may be expressed(e.g., in linear form for P_(PRACH)(i)) as follows:

{circumflex over (P)} _(PRACH)(i)=min({circumflex over (P)}_(PRACH)(i),{circumflex over (P)} _(CMAX)(j)), or  Equation (65)

{circumflex over (P)} _(PRACH)=min({circumflex over (P)} _(PRACH),{circumflex over (P)} _(CMAX)(j)),  Equation (66)

where subframe j may be the first subframe of the PRACH preamble.

In addition, to allow for the case of {circumflex over (P)}_(PRACH)being greater than {circumflex over (P)}_(CMAX)(i), in any equationwhere, amongst other channel power terms, {circumflex over (P)}_(PRACH)or {circumflex over (P)}_(PRACH)(i) is subtracted from {circumflex over(P)}_(CMAX)(i), the subtraction may be modified to prevent thecomputation of a negative linear power term as, for example,max(0,{circumflex over (P)}_(CMAX)(i)−{circumflex over (P)}_(PRACH)) ormax(0, {circumflex over (P)}_(CMAX)(i)−{circumflex over(P)}_(PRACH)(i)).

There may be transient periods at the start and/or the end of subframes,during which the subframe's power requirement may not apply. Examples ofsuch transient periods without SRS and with SRS are shown in FIGS. 13and 14, respectively.

In one embodiment, the transient periods, (e.g., between slots and/orsubframes), may be expanded. The transients periods may be expanded ifthe TA difference (e.g., between UL transmissions on different CCs) isbeyond a fixed threshold, a signaled threshold, or with no thresholdtest (e.g., unconditionally in the case of inter-band operation). FIGS.15 and 16 show examples of expanded transient periods for non-SRS andSRS transmissions, respectively.

Embodiments for applying per-symbol scaling are disclosed hereafter. Theper-symbol scaling may be applied after the conventional scaling forP_(CMAX)(i) has been applied.

The eNB may need to know that the WTRU is applying the per-symbolscaling. The embodiments disclosed above for an eNB to know that theWTRU is applying the rules for dropping SRS may be employed for thispurpose. The per-symbol scaling may be applied when there are two ormore TAGs, regardless of their TA difference.

In one embodiment, for per-symbol scaling, all symbols in the overlapmay be scaled by the same factor. The factor may be known to both theWTRU and the eNB. The factor may be a function of the number of CCs inthe overlap. The number of CCs may be the number of configured CCs, thenumber of activated CCs, or the number of CCs with grants in theaffected subframes. For the case of shortened subframes or formats, thenumber of CCs may be the respective number of CCs with transmittedsymbols in the overlap. This may be limited to the number of CCs per anyof these definitions using quadrature amplitude modulation (QAM).

The per-symbol scale factor may be 1/K, where K is the number of CCsdescribed above. The symbols in the overlapping portion, (e.g., the lastsymbol of a subframe in a less advanced TAG and the first symbol of thenext subframe in a more advanced TAG), may have its power scaled by 1/K.FIG. 17 shows an example in which per-symbol scaling is applied to thesymbols in the overlap. In this example, two CCs in TAG1 (the moreadvanced TAG) and two CCs in TAG2 (the less advanced TAG) are shown andsymbols 1702 are the symbols to which per-symbol scaling is applied.

Alternatively, a scale factor α/K may be used, where a may be aconstant, which may be signaled by the WTRU to the eNB, signaled by theeNB to the WTRU, a specified function of a signaled value(s), orspecified. α may be in the range 1≦α≦K.

In addition to applying the per-symbol scaling as described above, forexample to manage the average power of each CC such that it may be thesame before and after applying the per-symbol scaling to the symbols inthe overlapping portion, the power of the remaining symbols in thesubframe may be scaled by a different factor. For example, the symbolsin the overlapping portion and the remaining symbols may be scaled by ƒ₁and ƒ₂, respectively, where:

$\begin{matrix}{{f_{1} = \frac{2N_{symb}^{UL}}{1 + {K( {{2N_{symb}^{UL}} - 1} )}}}{{f_{2} = \frac{{K \cdot 2}N_{symb}^{UL}}{1 + {K( {{2N_{symb}^{UL}} - 1} )}}},}} & {{Equation}\mspace{14mu} (67)}\end{matrix}$

where N_(symb) ^(UL) is the number of SC-FDMA symbols in a slot of thesubframe, which may be 6 or 7.

An example of using two scaling factors, ƒ₁ (which may be used to scalethe symbols in the overlapping portion) and ƒ₂ (which may be used toscale the remaining symbols), including the constant α is as follows:

$\begin{matrix}{{f_{1} = {\frac{2N_{symb}^{UL}}{1 + {( {K/\alpha} )( {{2N_{symb}^{UL}} - 1} )}} = \frac{{\alpha \cdot 2}N_{symb}^{UL}}{\alpha + {K \cdot ( {{2N_{symb}^{UL}} - 1} )}}}}{f_{2} = {\frac{{( {K/\alpha} ) \cdot 2}N_{symb}^{UL}}{1 + {( {K/\alpha} )( {{2N_{symb}^{UL}} - 1} )}} = {\frac{{K \cdot 2}N_{symb}^{UL}}{\alpha + {K \cdot ( {{2N_{symb}^{UL}} - 1} )}}.}}}} & {{Equation}\mspace{14mu} (68)}\end{matrix}$

Alternatively, for per-symbol scaling, the first or last symbol in asubframe (or another subset of the symbols in the subframe which may bea fixed subset or a subset dependent on the overlap) may be scaled bythe factor ƒ₁ and the remaining symbols may not be scaled because, forexample, the factor ƒ₂ may be so close to unity for practicalcombinations of α, K, and N_(symb) ^(UL) so that that difference may beignored.

The embodiments above for per-symbol scaling may be limited to CCs usingQAM in the respective overlaps.

A power scale factor may be applied to the first and last symbols of CCsin a TAG when there is a transmission in more than one TAG.Alternatively, a power scale factor may be applied to the first and lastsymbols of CCs in a TAG when there was any transmission in another TAGin the last symbol of the previous subframe and/or will be anytransmission in another TAG in the first symbol of the next subframe.Alternatively, a power scale factor may be applied to the first symbolof CCs in a TAG when there was any transmission in another TAG in thelast symbol of the previous subframe, and a power scale factor may beapplied to the last symbol of CCs in a TAG if there will be anytransmission in another TAG in the first symbol of the next subframe. Inthese embodiments, the per-symbol scaling may be applied regardless ofwhich TAG is more or less advanced.

In a case where a power scale factor, (e.g., ƒ₁₂), is applied to boththe first and last symbols, the power of the remaining symbols in thesubframe may also be scaled by a different power scale factor, (e.g.,ƒ₂₂), for example to maintain the average power of each CC the samebefore and after applying the power scaling to the first and lastsymbols. The first subscript means the symbols in the overlap or theremaining symbols as in the above, and the second subscript means thetwo-symbol case.

$\begin{matrix}{{f_{12} = \frac{2N_{symb}^{UL}}{2 + {K( {{2N_{symb}^{UL}} - 2} )}}}{f_{22} = {\frac{{K \cdot 2}N_{symb}^{UL}}{2 + {K( {{2N_{symb}^{UL}} - 2} )}}.}}} & {{Equation}\mspace{14mu} (69)}\end{matrix}$

The two power scaling factors including the constant α may be written asfollows:

$\begin{matrix}{{f_{12} = {\frac{2N_{symb}^{UL}}{2 + {( {K/\alpha} )( {{2N_{symb}^{UL}} - 2} )}} = \frac{{\alpha \cdot 2}N_{symb}^{UL}}{{2\alpha} + {K \cdot ( {{2N_{symb}^{UL}} - 2} )}}}}{f_{22} = {\frac{{( {K/\alpha} ) \cdot 2}N_{symb}^{UL}}{2 + {( {K/\alpha} )( {{2N_{symb}^{UL}} - 2} )}} = {\frac{{K \cdot 2}N_{symb}^{UL}}{{2\alpha} + {K \cdot ( {{2N_{symb}^{UL}} - 2} )}}.}}}} & {{Equation}\mspace{14mu} (70)}\end{matrix}$

The above embodiments may be extended for the case of K being differentfor the first and last symbols of the subframe, denoted as K₁ andK_(2N), respectively. In this case the power scale factors may be, forexample, as follows:

$\begin{matrix}{{f_{13} = \frac{K_{2N}2N_{symb}^{UL}}{K_{1} + K_{2N} + {K_{1}{K_{2N} \cdot ( {{2N_{symb}^{UL}} - 2} )}}}}{f_{23} = \frac{K_{1}K_{2N}2N_{symb}^{UL}}{K_{1} + K_{2N} + {K_{1}{K_{2N} \cdot ( {{2N_{symb}^{UL}} - 2} )}}}}{{f_{33} = \frac{K_{1}2N_{symb}^{UL}}{K_{1} + K_{2N} + {K_{1}{K_{2N} \cdot ( {{2N_{symb}^{UL}} - 2} )}}}},}} & {{Equation}\mspace{14mu} (71)}\end{matrix}$

where ƒ₁₃ may be the power scale factor applied to the first symbol inthe subframe, ƒ₃₃ may be the power scale factor applied to the lastsymbol in the subframe, and ƒ₂₃ may be the power scale factor applied tothe remaining symbols in the subframe. The parameters K₁ and K_(2N), maybe replaced with K₁/α and K_(2N)/α, respectively.

The per-symbol scaling may be applied conditionally, for example, whenthere is more than one TAG, or when there is a particular type oftransmission in a subframe, (e.g., 16-QAM or 64-QAM).

The per-symbol scaling may be applied in a manner to avoid unnecessaryscaling when there is a scheduled SRS transmission. For example, whereone scale factor, 1/K, is used, if there is a 64-QAM transmission in anycell in subframe N, and if in a different TAG there was a PUCCH and/orPUSCH transmitted in the last symbol in subframe N−1, the WTRU may scalethe power of that first symbol of channels transmitted in subframe N by1/K, and if there is a 64-QAM transmission in any cell in the lastsymbol in subframe N and in a different TAG there will be transmissionin the first symbol in subframe N+1, the WTRU may scale the power ofthat last symbol of PUCCH and/or PUSCH transmitted in subframe N by 1/K.

A compensating factor may be included in determining P_(PUCCH), and/orP_(PUSCH) with UCI, for example to compensate for a small loss incurredby the per-symbol scaling as follows:

$\begin{matrix}{{{P_{PUCCH}(i)} = {\min \begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{P_{0\_ \; {PUCCH}} + {PL}_{c} + {h( {n_{CQI},n_{HARQ},n_{SR}} )} +} \\{{\Delta_{F\; \_ \; {PUCCH}}(F)} + {\Delta_{TxD}( F^{\prime} )} + {g(i)} + x}\end{Bmatrix}}},} & {{Equation}\mspace{14mu} (72)} \\{{{P_{{PUSCH},c}(i)} = {\min \begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{{10\mspace{11mu} {\log_{10}( {M_{{PUSCH},c}(i)} )}} + {P_{{O\; \_ \; {PUSCH}},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)} + x}\end{Bmatrix}}},} & {{Equation}\mspace{14mu} (73)}\end{matrix}$

where x is the compensating factor. The compensating factor may be afixed amount, or a function of the P_(PUCCH) and or P_(PUSCH), or afunction of the amount of overlap, and may be applied when scaling isperformed to avoid exceeding P_(CMAX) in the overlap. The compensatingfactor may be a certain value when per-symbol scaling is performed andmay be 0 dB if per-symbol scaling is not performed.

Embodiments for handling maximum power during an overlap are disclosedhereafter.

In certain embodiments, a transmit power may be determined for subframeN and may include scaling. Before transmission, and possibly allowingtime for the additional processing described below, a transmit power maybe determined for subframe N+1 and may include scaling.

Following, or in addition to, the above processing for subframes N andN+1, the WTRU may scale, further scale, rescale, or adjust thetransmission or the transmit power of channels in the overlappingportion, which may be in the more advanced TAG in subframe N+1 and theless advanced TAG in subframe N, for example to avoid exceeding amaximum power during the overlap. FIG. 18A shows an example in which thetransmit powers in the overlap are rescaled after the power isdetermined for the two adjacent subframes. The transmit power forsubframe N and subframe N+1 may be set by the conventional scalingrules, and rescaling may be applied to subframe N in the less advancedTAG (TAG2 in this example) and subframe N+1 in more advanced TAG (TAG1in this example) for example to avoid exceeding a maximum power duringthe overlap.

The scaling, rescaling, or adjusting may be applied, (e.g., using theconventional scaling priorities), as follows, with i and i+1 replacing Nand N+1 (where limiting the power may be to the quantity P_(CMAX) _(—)_(ov)(i)):

$\begin{matrix}{{{{w(i)} \cdot ( {{{\hat{P}}_{PUCCH}( {i,{{TAG}\; 2}} )} + {{\hat{P}}_{PUCCH}( {{i + 1},{{TAG}\; 1}} )}} )} \leq {{{\hat{P}}_{{CMAX}\; \_ \; {ov}}(i)} - {{\hat{P}}_{PRACH}( {{i + 1},{{TAG}\; 1}} )}}},} & {{Equation}\mspace{14mu} (74)} \\{{{{w(i)} \cdot ( {{\sum\limits_{c = j}\; {{\hat{P}}_{{PUSCH},c}( {i,{{TAG}\; 2}} )}} + {\sum\limits_{c = j}\; {{\hat{P}}_{{PUSCH},c}( {{i + 1},{{TAG}\; 1}} )}}} )} \leq {{{\hat{P}}_{{CMAX}\; \_ \; {ov}}(i)} - {{\hat{P}}_{PRACH}( {{i + 1},{{TAG}\; 1}} )} - {{\hat{P}}_{PUCCH}( {i,{{TAG}\; 2}} )} - {{\hat{P}}_{PUCCH}( {{i + 1},{{TAG}\; 1}} )}}},} & {{Equation}\mspace{14mu} (75)} \\{{{{w(i)} \cdot ( {{\sum\limits_{c \neq j}\; {{\hat{P}}_{{PUSCH},c}( {i,{{TAG}\; 2}} )}} + {\sum\limits_{c \neq j}\; {{\hat{P}}_{{PUSCH},c}( {{i + 1},{{TAG}\; 1}} )}}} )} \leq {{{\hat{P}}_{{CMAX}\; \_ \; {ov}}(i)} - {{\hat{P}}_{PRACH}( {{i + 1},{{TAG}\; 1}} )} - {{\hat{P}}_{PUCCH}( {i,{{TAG}\; 2}} )} - {{\hat{P}}_{PUCCH}( {{i + 1},{{TAG}\; 1}} )} - {\sum\limits_{c = j}\; {{\hat{P}}_{{PUSCH},c}( {i,{{TAG}\; 2}} )}} - {\sum\limits_{c = j}\; {{\hat{P}}_{{PUSCH},c}( {{i + 1},{{TAG}\; 1}} )}}}},} & {{Equation}\mspace{14mu} (76)}\end{matrix}$

where {circumflex over (P)}_(X)(i,TAGy) may be the linear form oftransmit power in channel X, (e.g., X=PUCCH), in subframe i, in TAG y.TAG1 is more advanced than TAG2, (e.g., for any given subframe, channelsin TAG1 are transmitted earlier by the WTRU than are channels in TAG2).The numbering of the TAGs is for example purposes. j may be a servingcell that has PUSCH transmission with UCI.

In certain embodiments, P_(CMAX) _(—) _(ov)(i) may be the power limit(e.g., the maximum power) for the WTRU for the sum of the powers of thechannels in the overlap of subframes i and i+1 or the power limit (e.g.,the maximum power) for the WTRU for the sum of the powers of the CCs inthe overlap of subframes i and i+1. P_(CMAX) _(—) _(ov)(i) (or in linearform {circumflex over (P)}_(CMAX) _(—) _(ov)(i)), may be a function ofP_(CMAX)(i) and/or P_(CMAX)(i+1) (or {circumflex over (P)}_(CMAX)(i)and/or {circumflex over (P)}_(CMAX)(i+1)) for example, α·min({circumflexover (P)}_(CMAX)(i),{circumflex over (P)}_(CMAX)(i+1)), wherein α maybe 1. Alternatively, it may be a function of {circumflex over(P)}_(CMAX)(i) and {circumflex over (P)}_(CMAX)(i+1) that takes intoaccount the amount of the overlap. α may be a constant and may be the αdisclosed above for per-symbol scaling.

Linear power quantities to the right of the inequalities in the aboveequations may be after scaling has been applied in the previous step.

As an alternative to using the conventional scaling priorities forrescaling, the channels in subframe N in TAG2 and the channels insubframe N+1 in TAG1 may be rescaled equally.

As an alternative to rescaling only the channels in subframe N in TAG2and the channels in subframe N+1 in TAG1, the channels in subframe N andsubframe N+1 may be rescaled.

In certain embodiments, a WTRU may determine the power(s) for thechannel(s) in subframe N and N+1 ignoring the overlap and may use thosepowers for the channel(s) in the non-overlapping parts of subframes Nand N+1, respectively. The WTRU may determine the powers for thechannels in the overlap and use those powers for the channels in theoverlap. For example, a WTRU may scale the channels in thenon-overlapping regions separately from the overlapping region(s)instead of scaling for the entire subframe and then rescaling oradjusting in the overlap. The WTRU may use the same individual channelpowers before scaling for the overlap and non-overlap regions and thesechannel powers may be determined by the WTRU as if the overlap did notexist.

The WTRU may scale or otherwise adjust the powers of the channels in theoverlap of subframes N and N+1 to not exceed a maximum output power forthe overlap, e.g., P_(CMAX) _(—) _(ov)(N) (or P_(CMAX) _(—) _(ov)(i)using the “i” notation) which may also be referred to as P_(CMAX) _(—)_(ov).

FIG. 18B shows an example in which the transmit powers in the overlapare scaled separately from the transmit powers in the non-overlappingregions and the transmit powers in the overlap are scaled as needed tonot exceed P_(CMAX) _(—) _(ov). Transmit powers for subframe N and N+1outside of the overlap are scaled as needed to not exceed P_(CMAX)(N)and P_(CMAX)(N+1) in subframes N and N+1, respectively, outside of theoverlap. Transmit powers in the overlap are scaled as needed to notexceed P_(CMAX) _(—) _(ov) in the overlap. It is noted that scaling isan example and any actions may be taken, such as adjusting power ordropping channels, to not exceed P_(CMAX) _(—) _(ov) in the overlap orto not exceed P_(CMAX)(N) and/or P_(CMAX)(N+1) in subframes N and N+1,respectively, outside of the overlap and still be consistent with theembodiments disclosed herein.

Taking actions (e.g., scaling or adjusting power or dropping channels)and/or making the related decisions for those actions (e.g., determiningwhether a maximum power would be or is to be exceeded) separately forthe channels or transmit powers in the non-overlapping regions and thechannels or transmit powers in the overlap is an example and the actionsmay be taken and the decisions may be made separately or together andmay be taken or made in any order to not exceed P_(CMAX) _(—) _(ov) inthe overlap or to not exceed P_(CMAX)(N) and/or P_(CMAX)(N+1) insubframes N and N+1, respectively, outside of the overlap and still beconsistent with the embodiments disclosed herein. Decisions ordeterminations such as those regarding whether a maximum power would beor is to be exceeded as well as any related actions may be performedusing values, sums and comparisons in linear or log form.

P_(CMAX) _(—) _(ov)(i) may be a configured value which may be chosen bythe WTRU. It may be defined to have a range with a high value (e.g.,P_(CMAX) _(—) _(ov) _(—) _(H)(i)) and a low value (e.g., P_(CMAX) _(—)_(ov) _(—) _(L)(i)) and/or it may be defined to have one value. Ifdefined to have a range, the WTRU may choose a value in that range forP_(CMAX) _(—) _(ov)(i). For the overlap, the WTRU may not be permittedto exceed the power of its chosen value (e.g., in case of a range), thehigh value, or the single value. P_(CMAX) _(—ov) (i), P_(CMAX) _(—)_(ov) _(—) _(H)(i), and P_(CMAX) _(—) _(ov) _(—) _(L)(i) may correspondto (e.g., be applicable to) the overlap between subframe i and i+1.

P_(CMAX) _(—) _(ov)(i) or P_(CMAX) _(—) _(ov) _(—) _(H)(i) may be atleast one of the following: P_(PowerClass) or the smaller of the sum ofthe P_(EMAX),c values of the CCs in the overlap and P_(PowerClass),(e.g., MIN{10 log₁₀ Σp_(EMAX,c), P_(PowerClass)}). The values, sums andcomparisons may be in linear or log form.

P_(CMAX) _(—) _(ov) _(—) _(L)(i) may be at least one of the followingwhere values, sums and comparisons may be in linear and/or log form.P_(CMAX) _(—) _(ov) _(—) _(L)(i) may be a function of the P_(CMAX) _(—)_(L) _(—) _(CA) values for subframes i and/or i+1 such as one of the twovalues or the minimum of the two values, (e.g., MIN{P_(CMAX) _(—) _(L)_(—) _(CA)(i), P_(CMAX) _(—) _(L) _(—) _(CA)(i+1)}).

P_(CMAX) _(—) _(ov) _(—) _(L)(i) may be a function of the P_(CMAX) _(—)_(L,c) values for the CCs transmitted in subframe i and/or i+1, forexample the sum of the P_(CMAX) _(—) _(L,c) value(s) in subframe i forthe less advanced CC(s) plus the sum of the P_(CMAX) _(—) _(L,c)value(s) in subframe i+1 of the more advanced CC(s) where such total maybe capped by P_(PowerClass), for example, as follows:

P _(CMAX) _(—) _(ov) _(—) _(L)(i)=MIN[10 log 10(sum(p _(CMAX) _(—)_(L,c)(k))),P _(PowerClass)],  Equation (77)

where k=i for the CC(s) in the TAG that is less advanced and k=i+1 forthe CC(s) in the TAG that is more advanced. For example, for the case of2 CCs (c0 and c1), it may be that in the equation above, k=i for c=c0and i+1 for c=c1, where c0 is the carrier in the TAG that is lessadvanced than that of c1, and c1 is the carrier in the TAG that is moreadvanced than that of c0.

In another example:

P _(CMAX) _(—) _(ov) _(—) _(L)(i)=MIN[10 log 10(sum(MIN[p_(EMAX,c)(k)/Δt _(C,c)(k),_(PowerClass)/(mpr _(c)(k)·a-mpr _(c)(k)·Δt_(C,c)(k)·Δt _(IB,c)(k),p _(PowerClass)/(pmpr _(c)(k)·Δt _(C,c)(k])),P_(PowerClass)],  Equation (78)

where, for example for 2 CCs (c0 and c1), it may be that k=i for c=c0and i+1 for c=c1, c0 is the carrier in the TAG that is less advancedthan that of c1, and c1 is the carrier in the TAG that is more advancedthan that of c0.

P_(CMAX) _(—) _(ov) _(—) _(L)(i) may be a function of the P_(CMAX) _(—)_(L,c) values for the CCs transmitted in subframe i and/or i+1, forexample the sum of the lower P_(CMAX) _(—) _(L,c) value (from subframe ior i+1) for each CC that may overlap where such sum may be capped byP_(PowerClass). For example, P_(CMAX) _(—) _(ov) _(—) _(L)(i) may berepresented as:

P _(CMAX) _(—) _(ov) _(—) _(L)(i)=MIN[10 log 10(sum(MIN[p _(CMAX) _(—)_(L,c)(i),p _(CMAX) _(—) _(L,c)(i+1)]),P _(PowerClass)].  Equation (79)

P_(CMAX) _(—) _(ov) _(—) _(L)(i) may be a function of the P_(CMAX) _(—)_(L,c) values for the CCs transmitted in subframe i and/or i+1, forexample K×the lowest P_(CMAX) _(—) _(L,c) value (from subframe i or i+1)among the CCs that may overlap, where K is the number of CCs that mayoverlap and the resulting value may be capped by P_(PowerClass).

For example for 2 CCs, c0 and c1:

P _(CMAX) _(—) _(ov) _(—) _(L)(i)=MIN[10 log 10(2×MIN[p _(CMAX) _(—)_(L,c0)(i),p _(CMAX) _(—) _(L,c0)(i+1),p _(CMAX) _(—) _(L,c1)(i),p_(CMAX) _(—) _(L,c1)(i+1)]),P _(PowerClass)].  Equation (80)

Which embodiment is used for determining P_(CMAX) _(—) _(ov)(i) may bebased on at least whether the overlapping CCs are intra-band orinter-band.

The subframe region or time which may be considered the overlap region,for example the region of the subframes(s) to which P_(CMAX) _(—)_(ov)(i) may apply and/or to which rules, such as scaling ortransmission rules for overlap may apply may be defined based on the ULtiming of the start and end of each subframe for each CC or each TAG orone or more CCs in each TAG. FIG. 19 shows an example overlap regionbased on UL timing. In FIG. 19, the section 1902 with the diagonalhatching may be considered the overlap region for these CCs or TAGs.

It should be noted that there may be a transient region defined for eachCC which may begin before what is considered the actual start of thesubframe and/or which may end after what is considered the actual end ofthe subframe. This transient region may allow for the power to changefrom one subframe to another and/or may be a region of the subframe notincluded in power testing. Since the power of a CC may change during thetransient region, there may be the possibility of exceeding a powerlimit in that region.

In one embodiment, what is to be considered the overlap region, (forexample for applying the embodiments for handling maximum power duringoverlap), may include (e.g., also include) the transient regions whichmay be at the beginning and/or end of each subframe. FIG. 20 shows anexample of transient regions at the end of subframe i of the moreadvanced TAG (TAG2) and at the beginning of subframe i+1 of the lessadvanced TAG (TAG1). As shown in FIG. 20, the transient regions beforethe beginning and after the end of each subframe may be included in theregion considered to overlap, e.g., based on UL subframe timing.

The measured maximum output power P_(UMAX) over serving cells may bewithin the following range:

P _(CMAX) _(—) _(L) _(—) _(CA) −T(P _(CMAX) _(—) _(L) _(—) _(CA))≦P_(UMAX) ≦P _(CMAX) _(—) _(H) _(—) _(CA) +T(P _(CMAX) _(—) _(H) _(—)_(CA)),  Equation (81)

where T(P) represents a tolerance value for power P.

An allowance for the overlapping transmissions when there are multipletiming advances or multiple TAGs may be made by changing the toleranceof P_(UMAX), T(P_(CMAX)). Such allowance may be applicable when there ismore than one TAG, or when there is more than one TAG and the timingdifference between TAGs is greater than a threshold. The allowance maybe an increase or a decrease by some amount, for example, a fixed amount(e.g., +0.5 dB), a fixed amount that is a function of P_(CMAX), anamount or amounts that is/are a function of other quantities signaled bythe eNB, a new quantity or quantities signaled by the eNB, and/or afunction or functions thereof.

The tolerance change (which may be an addition or subtraction) may beapplicable to one or more of the lower and upper limits of P_(UMAX). Forthe case in which T-MPR is not included in P_(CMAX) _(—) _(L) _(—)_(CA), or other cases, an additional tolerance may be subtracted fromthe left side of equation (81) when there is an overlap condition in asubframe as follows:

P _(CMAX) _(—) _(L) _(—) _(CA) −T(P _(CMAX) _(—) _(L) _(—)_(CA))−Toverlap≦P _(UMAX) ≦P _(CMAX) _(—) _(H) _(—) _(CA) +T(P _(CMAX)_(—) _(H) _(—) _(CA)),  Equation (82)

where Toverlap may be equal to T-MPR or a function of T-MPR.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

1. A method for power control for wireless transmissions on multiplecomponent carriers associated with multiple timing advances, the methodcomprising: a wireless transmit/receive unit (WTRU) calculating atransmit power of physical channels in each subframe to be transmittedon a plurality of component carriers that belong to at least twodifferent timing advance groups, wherein each timing advance group isassociated with a separate timing advance value for uplinktransmissions; the WTRU scaling a transmit power of at least one of thephysical channels in each subframe on a condition that a sum of atransmit power of the physical channels in the same subframe is toexceed a configured maximum WTRU output power for that subframe; and theWTRU adjusting the transmit power of at least one of the physicalchannels on a condition that a sum of a transmit power of the physicalchannels in an overlapping portion of a subframe of a less advanced TAGand a next subframe of a more advanced TAG is to exceed a configuredmaximum WTRU output power for overlap such that a sum of a transmitpower of the physical channels in the overlapping portion does notexceed the configured maximum WTRU output power for overlap.
 2. Themethod of claim 1 wherein the transmit power of the physical channels isadjusted in an order based on a physical channel priority.
 3. The methodof claim 1 wherein the configured maximum WTRU output power for overlapis determined as a function of configured maximum WTRU output powers fortwo consecutive overlapping subframes.
 4. The method of claim 1 whereinthe configured maximum WTRU output power for overlap is same as one ofconfigured maximum WTRU output powers for the two consecutiveoverlapping subframes.
 5. The method of claim 1 wherein the configuredmaximum WTRU output power for overlap is selected by the WTRU from arange of a lower limit and a higher limit.
 6. The method of claim 1wherein the WTRU drops a sounding reference signal (SRS) on a conditionthat another physical channel is scheduled to be transmitted on a symbolthat overlaps either partially or fully to the SRS on any componentcarrier.
 7. The method of claim 1 further comprising: the WTRUcalculating a transmit power for each sounding reference signal (SRS) tobe transmitted on component carriers, wherein the WTRU drops the SRS ona condition that a sum of the transmit power for the SRS on multiplecomponent carriers is to exceed an available power.
 8. The method ofclaim 1 further comprising: the WTRU sending a power headroom report toa network, wherein the power headroom report includes a configuredmaximum WTRU output power for a present subframe on a condition that theconfigured maximum WTRU output power does not equal to a configuredmaximum WTRU output power for any serving cell or a sum of configuredmaximum WTRU output power for serving cells.
 9. The method of claim 1further comprising: the WTRU calculating a transmit power for a physicalrandom access channel (PRACH); and the WTRU transmitting the PRACH,wherein a transmit power for the PRACH is constant over an entire PRACHpreamble at a power level determined for a first subframe of the PRACH.10. The method of claim 1 wherein a guard symbol is included in acomponent carrier to avoid overlapping channels.
 11. A wirelesstransmit/receive unit (WTRU) for power control for wirelesstransmissions on multiple component carriers associated with multipletiming advances, the WTRU comprising: a processor configured tocalculate a transmit power of physical channels in each subframe to betransmitted on a plurality of component carriers that belong to at leasttwo different timing advance groups (TAGs), wherein each TAG isassociated with a separate timing advance value for uplinktransmissions; the processor is further configured to scale a transmitpower of at least one of the physical channels in each subframe on acondition that a sum of a transmit power of the physical channels in thesame subframe is to exceed a configured maximum WTRU output power forthat subframe; and the processor is further configured to adjust atransmit power of at least one of the physical channels on a conditionthat a sum of a transmit power of the physical channels in anoverlapping portion of a subframe of a less advanced TAG and a followingconsecutive subframe of a more advanced TAG is to exceed a configuredmaximum WTRU output power for overlap such that a sum of a transmitpower of the physical channels in the overlapping portion does notexceed the configured maximum WTRU output power for overlap.
 12. TheWTRU of claim 11 wherein the processor is configured to adjust thetransmit power of the physical channels in an order based on a physicalchannel priority.
 13. The WTRU of claim 11 wherein the processor isconfigured to determine the configured maximum WTRU output power foroverlap as a function of configured maximum WTRU output powers for twoconsecutive subframes.
 14. The WTRU of claim 11 wherein the configuredmaximum WTRU output power for overlap is same as one of configuredmaximum WTRU output powers for the two consecutive overlappingsubframes.
 15. The WTRU of claim 11 wherein the processor is configuredto select the configured maximum WTRU output power for overlap from arange of a lower limit and a higher limit.
 16. The WTRU of claim 11wherein the processor is configured to drop a sounding reference signal(SRS) on a condition that another physical channel is scheduled to betransmitted on a symbol that overlaps either partially or fully to theSRS on any component carrier.
 17. The WTRU of claim 11 wherein theprocessor is configured to calculate a transmit power for each soundingreference signal (SRS) to be transmitted on component carriers, and dropthe SRS on a condition that a sum of the transmit power for the SRS onmultiple component carriers is to exceed an available power.
 18. TheWTRU of claim 11 wherein the processor is configured to send a powerheadroom report to a network including a configured maximum WTRU outputpower for a present subframe on a condition that the configured maximumWTRU output power does not equal to a configured maximum WTRU outputpower for any serving cell or a sum of configured maximum WTRU outputpower for serving cells.
 19. The WTRU of claim 11 wherein the processoris configured to calculate a transmit power for a physical random accesschannel (PRACH), and transmit the PRACH, wherein a transmit power forthe PRACH is constant over an entire PRACH preamble at a power leveldetermined for a first subframe of the PRACH.
 20. The WTRU of claim 11wherein a guard symbol is included in a component carrier to avoidoverlapping channels.